11pm: Time to wrap up this live blog for the evening, with a summary of the latest events.

• At least 45 people appear to have been killed in Yemen after security forces – including some said to be snipers – opened fire in Sana'a. A government minister resigned and quit the ruling party of President Ali Abdullah Saleh.

• President Obama warned in a televised statement supporting the UN resolution against Libya's Gaddafi regime: "Let me be clear: these terms are not negotiable. These terms are not subject to negotiation."

• Gaddafi's forces continue to close in on Benghazi, while fighting continued to be heard in and around Mizrata, despite statements by Libyan ministers saying that government forces were abiding by a ceasefire announced earlier.

• In Bahrain the government ordered the destruction of the statue within Pearl Square that had been a symbol of protests in the Gulf state. Foreign minister Sheikh Khaled bin Ahmed al-Khalifa said the army destroyed the monument because "it was a bad memory."

For more of the latest news, the Guardian's full coverage of the protests in north Africa and the Middle East continues here.

10.27pm: How committed is the US to actively participating in the UN-sanctioned use of force against Libya? Yahoo's Laura Rozen has disturbing details of a meeting today between Obama and congressional leaders:

Obama told Congressional leaders that "he had not authorised troops on the ground or airplanes," a staffer to one of the Congress members briefed Friday said on condition of anonymity. "He stressed the US is diplomatically supporting the no-fly zone, not the enforcement itself."

10pm: Fighting and shelling has been going on in Misrata, despite the Gaddafi regime's talk of a ceasefire, this evening, reports Reuters:

Shelling began early in the morning and tapered off after nightfall, the resident named Mohammad said. Gaddafi battalions backed by about 40 tanks fought with rebels in the city for most of the afternoon before the pulled out again, he said. Doctors in the city reported at least 38 dead from what they called indiscriminate shelling and heavy fighting when the army entered Misrata with Russian-made T-72 and T-55 tanks, armoured troop carriers and pick-up trucks with heavy machine guns. "They were attacked by the rebels," Mohammad said. "We managed to destroy 11 of their vehicles, including a couple of tanks. We took one of their tanks and five pick-up trucks. The battle lasted for about four to five hours before they left." The army entered the city of 300,000 shortly after Foreign Minister Moussa Koussa said Libya had decided to halt all military operations in the country to protect civilians and comply with the UN resolution, Mohammad said.

9.41pm: Appearing on CNN just now, the US's UN ambassador Susan Rice said Gaddafi's forces were in violation of the UN Security Council resolution through their advance upon Benghazi, and warned of "swift and sure consequences including military action".

9.23pm: Libya's deputy foreign minister Khaled Kaim has been holding another press conference, claiming that pro-Gaddafi forces have conducted no military operations since starting a ceasefire today.

Via Reuters and al-Jazeera:

"We have had no bombardment of any kind since the ceasefire was declared," Deputy Foreign Minister Khaled Kaim told reporters when asked about reports of continued government operations in Misrata and other parts of the country.

"As for the presence of the army in Libyan cities, we consider that important for the security of citizens. It does not violate the ceasefire," he said, adding:

The ceasefire means no military operations, big or small. The other point is that armed forces are now outside Benghazi and have no intention of entering the city.

Kaim's remarks are in contrast by multiple reports of fighting all day in Misrata, as well as other towns, with talk of a massacre taking place in Ajdabiya and residents fleeing to Benghazi.

9pm: Tom Finn in Sana'a writes for the Guardian on the bloody events in Yemen today:

"The most common injuries were bullet wounds to the chest and the head, although some are suffering from exposure to teargas," said one doctor who did not wish to be named. "They shot people in the back of the head as they were running away," said Mohammed al-Jamil, an Indian doctor treating the wounded with specks of blood on his hands and face. "Whoever did this wanted these people to die," he added, tearing open a box of syringes. Witnesses said children were among the dozens wounded by gunfire. "My brother is 12 years old, they shot him twice, once in the arm and once in the leg," shouted a young man through a crackling microphone to a roaring crowd of thousands outside the mosque.

8.38pm: Today's violence in Yemen has forced open the cracks in the ruling party of President Ali Abdullah Saleh.

With some 40 people killed by snipers and other security forces, tourism minister Nabil Hasan al-Faqih became the first cabinet member to defect, resigning his post and quitting the ruling party. The head of the party's foreign affairs committee also left, as did a former ambassador to Russia.

A member of the ruling party's central committee, Jalal Faqira, who heads the political science department at Sanaa University, also resigned from the party along with another 50 professors.

8.21pm: How soon before the no-fly, no-drive zone in Libya is enforced by US forces? According to US Air Force chief of staff Norton Schwartz, speaking to senators in Washington yesterday and reported by Foreign Policy – plans to impose a no-fly zone in a few days were "overly optimistic" and said: "It would take upwards of a week."

When's the last time a U.S. president launched military action while outside of the U.S.? Mike Memoli

mikememoli

As it happens, Obama is off on a tour of South America tonight for five days, and returns to Washington on Wednesday – hence the tweet above by Mike Memoli, in the Chicago Tribune/LA Times Washington bureau. If Schwartz is right then Obama will be back in time.

8.03pm: The White House has posted the full text of Obama's statement on Libya online:

Now, here is why this matters to us. Left unchecked, we have every reason to believe that Gaddafi would commit atrocities against his people. Many thousands could die. A humanitarian crisis would ensue. The entire region could be destabilized, endangering many of our allies and partners. The calls of the Libyan people for help would go unanswered. The democratic values that we stand for would be overrun. Moreover, the words of the international community would be rendered hollow. And that's why the United States has worked with our allies and partners to shape a strong international response at the United Nations. Our focus has been clear: protecting innocent civilians within Libya, and holding the Gaddafi regime accountable.

7.48pm: Bahrain's foreign minister Sheikh Khaled bin Ahmed al-Khalifa says foreign troops from other Gulf states will remain for as long as it took to bring calm.

At a press conference, Reuters reports, Sheikh Khaled said the role of the foreign forces would be limited to guarding strategic assets such as oil facilities, and they will not be involved in quelling protests.

However, TV footage showed forces from the Gulf Cooperation Council guarding the area around Pearl Square, the focal point of protests which was demolished earlier today. Shiekh Khalid told reporters in Manama that the army destroyed the monument because "it was a bad memory."

Mourners at the funeral of activist Ahmed Farhan, killed on Wednesday, were reported chanting "death to al-Khalifa" and "death to al-Saud", a reference to the royal families of Bahrain and Saudi Arabia. From Reuters:

Sheikh Issa Qassim, Bahrain's most influential Shia cleric, said in his Friday sermon that Gulf troops would have been better off helping Palestinians in Gaza than entering Bahrain and thanked those who died or resigned in the uprising. "The violence of the authorities has created a deep, wide and dangerous wound between the government and people," he said. "The government wants to break our will so we give up our calls for substantial and meaningful reforms, but they will never break our will. They can use tanks and planes to smash our bodies but will never break our souls and our will for reforms." Sheikh Khaled said, however, that the royals had done their utmost to push for dialogue, allowing protests and offering assurances, but the opposition had rejected talks and started blocking main streets, while civilians began to clash daily. "In volatile situations you do expect violence to happen but there is no systematic violence against the people," he said.

Sheikh Khaled also condemned what he said was Iran's interference in Bahrain's internal affairs.

7.23pm: Al-Jazeera is reporting that pro-Gaddafi forces are advancing at a rapid pace towards Benghazi on Friday evening, despite the ceasefire that the regime declared earlier today.

According to its correspondents in Benghazi, the Gaddafi regime's forces are fighting with rebels in the towns of al-Magroun and Slouq, just 50km outside Benghazi.

7pm: An round-up of today's action in the Middle East and north Africa, via the Associated Press:

Yemen

Security forces open fire on tens of thousands of anti-government protesters flooding into a square in the capital, Sanaa, after prayers, killing at least 40 people and injuring hundreds. President Ali Abdullah Saleh declares a nationwide state of emergency. Friday's protests were the largest yet — and solicited the most violent response — in the popular uprising that started last month.

Libya

The regime of Muammar Gaddafi responds to a UN-backed no-fly zone and the threat of military intervention by announcing an immediate cease-fire with the Libyan rebels seeking to oust him. But both the international community and the rebels remain skeptical as regime forces continue to strike at least two rebel-held towns.

Syria

Syrian security forces disperse protesters in two towns, Syria's state media report in what appeared to be the gravest unrest for years in one of the Middle East's most repressive regimes. Human rights activists also say security forces disperse about a dozen protesters calling for more freedoms in Damascus, the third small rally in the capital this week.

Bahrain

Authorities in Bahrain demolish the huge white monument in Pearl Square where members of the tiny island kingdom's Shiite majority have protested to demand greater rights from the Sunni monarchy. The unrest in Bahrain, which has killed at least 12 people, has sparked regional sectarian tensions, with Saudi Arabia and other Sunni Gulf states sending troops, while Iran withdrew its ambassador in protest.

Iraq

Thousands of protesters rally in mostly Shia cities across Iraq to condemn what some call "sectarian attacks" by security forces in Bahrain against Shia protesters. The deployment of troops to Bahrain by the Gulf's Sunni nations could worsen relations between Iraq and Saudi Arabia, which views Iraq's Shia-dominated government as an Iranian pawn.

Iran

A senior Iranian cleric, Ayatollah Ahmad Jannati, urges Bahrain's majority Shia to keep up their protests – until death or victory – against Bahrain's Sunni monarchy. Bahraini and Iranian Shia have no apparent direct links, but the tiny island kingdom figures strongly into larger regional questions. Tehran protested when Saudi troops and other Gulf forces moved into Bahrain.

6.40pm: Today's statement by Obama was a fairly punchy one – reassuring US citizens that America is not planning to deploy ground troops while making clear that the US military will play its part – "as part of an international coalition" – in enforcing the UN resolution.

6.33pm: Obama's statement continues:

I also want to be clear about what we not be do – the US is not going to deploy ground troops into Libya. And we are not going to use force beyond a defined goal, specifically: the protection of civilians in Libya."

Without such action, according to Obama, there was every reason to believe Gaddafi would commit atrocities and that thousands could die as a result.

He mentions that "members of the Arab League have already committed to take a leadership role" – but makes clear that the US will be taking a significant role itself.

As of now, no Arab League countries have gone on the record as offering forces to the sanctions – although Jordan, the UAE and Qatar are the most likely participants.

6.28pm: If others failed to act against the Gaddafi regime, "the words of the international community would be hollow," says Obama.

The UN security council was responding to calls for action by the Libyan people and the Arab League, says Obama, and includes the enforcement of a no-fly zone and strengthens sanctions against Libya's government:

Now, once more Muammar Gaddafi has a choice - the resolution that was passed lays out very clear conditions that must be met.... A ceasefire must be implemented immediately. That means all attacks against all civilians must stop.

Gaddafi must stop and pull back his troops from Benghazi and other cities, and allow water and power supplies to be reconnected and humanitarian assistance allowed in for the people of Libya, Obama said, adding:

Let me be clear: these terms are not negotiable. These terms are not subject to negotiation. If Gaddafi does not comply, the international community will impose consequences, and the resolution will be enforced through military action.

6.20pm: Obama speaks. "In the last few weeks the world has watched the events in Libya with hope and alarm," he begins, saying that demonstrations in Libya "were met with an iron fist" by the Gaddafi regime:

Muammar Gaddafi clearly lost the confidence of his own people and his legitimacy to lead.

Gaddafi, Obama says, "chose the path of brutal suppression," listing attacks on hospitals and other sites as part of a "campaign of intimidation and repression".

6.05pm: Still waiting on Obama to appear. Meanwhile, CNN's Wolf Blitzer is explaining to viewers the discrepancy between the strength of the US air force and Gaddafi's military. "It's like the Los Angeles Lakers versus a high school team, if you will," he says, using a basketball simile.

5.45pm: President Obama will be making a statement on the subject of Libya from the East Room of the White House, sometime after 2pm ET (6pm GMT).

This is Richard Adams in the Guardian's Washington bureau, and we'll be live blogging Obama's remarks as they happen.

5.33pm: The Guardian's Richard Norton-Taylor and Nick Hopkins report that RAF Tornado and Typhoon ground attack jets are expected to fly to bases in the Mediterranean tomorrow, as part of the growing international military presence:

Britain is also expected tomorrow to set up a joint command centre with the US and France to coordinate operations which could include a number of countries, including Canada and Denmark. In further evidence of continuing pressure on Gaddafi despite the apparent ceasefire, ambassadors from Nato's 28 member nations are due to meet on Saturday to lend added support to the UN-backed plans for a no-fly zone and humanitarian operations.

5.03pm: Here's a summary of events so far today:

• The Libyan government announced a ceasefire in the face of the imminent threat of international military intervention. The statement by foreign minister, Mussa Kusa, came after France said airstrikes could be launched within hours in the wake of the resolution for a no-fly zone, passed by the UN security council.

• Despite the announcement, bombardment of opposition-held territory by Gaddafi's forces continued with 25 people killed in the eastern city of Misrata according to a doctor. The opposition council in Benghazi rejected the ceasefire amid the continued attacks and US secretary of state Hillary Clinton demanded to see "action on the ground", rather than just words.

• More than 40 people were reported killed and at least 300 injured in Yemen after Yemeni security forces and unidentified snipers opened fire on anti-government protesters after Muslim prayers in the capital, Sana'a. President Ali Abdullah Saleh, the target of the demonstrators, responded by declaring a state of emergency. US president Barack Obama condemned the violence.

• There have been anti-government protests reported in Syria, including in the cities of Damascus, Homs, Dara and Banias.

• The Bahraini authorities have destroyed Pearl roundabout, where anti-government protesters camped for weeks before being violently removed. The giant white landmark over the roundabout was removed and the roundabout was left a mess of soil and debris.

4.55pm: My colleague Owen Bowcott writes that the US has condemned the violence in Yemen today, despite its close ties with President Ali Abduallah Saleh.

President Obama has condemned the shooting of pro-democracy demonstrators in Yemen and demanded that those responsible be held to account. He said there should be an "open and transparent process that addresses the legitimate concerns of the Yemeni people, and provides a peaceful, orderly and democratic path to a stronger and more prosperous nation". How swiftly times and priorities change. Less than eighteen months ago, according documents recently released by Wikileaks, the US was involved in secret negotiations with the Yemeni president, Ali Abdullah Saleh, to obtain permission for covert air strikes against Al Qaida groups in the Arabian peninsula. Senior US officials did not want knowledge of their involvement revealed. In a meeting with General David Petraeus, then head of US central command, Saleh admitted lying to his population about the strikes. "We'll continue saying the bombs are ours, not yours," Saleh told Petraeus on 2 January last year. Now political 'transparency' is the priority.

4.49pm: Following in the footsteps of Hillary Clinton, French Foreign minister Alain Juppe has given a cautious response to the Gaddafi regime's declared ceasefire. He told Reuters:

We have to analyse the conditions of the ceasefire. It has to be on all of the territory of Libya and not only Benghazi, and we think that Libya must comply with all the resolutions of the (UN) security council.



Regarding military strikes, he added:

"We are ready but I cannot give you more details."

4.46pm: More from Cameron, who wasn't planning to address the Scottish conference on Libya until the events of the past 24 hours changed everything. Justifying British military action, he said:

This is where our ideals and our interests come together and I know that the British people. as they always do at such times of difficulty, they will unite behind the action we are taking.

4.37pm: David Cameron is speaking about Libya at the Scottish Conservative conference.

He quotes Gaddafi's pledge last night that there would be "no mercy". That is why Cameron took action to "stop this inhumanity", the prime minister says.

He is going through much of what he said in the House of Commons earlier (the three-pronged test for intervention). He gets applause when he mentions Gaddafi's crimes against "Scotland specifically", referring to the Lockerbie bombing.

He insists this will be no Iraq. "The people of Libya don't want that [occupation]." he says, nor does Britain or its allies.

4.32pm: Despite all evidence to the contrary, the Libyan government has claimed that it has started the ceasefire and wants Turkey and Malta to "supervise and help implement the ceasefire". Government spokesman Mussa Ibrahim told Reuters:



"Libya has already implemented the ceasefire. We have not carried out any military operations today on Misrata or anywhere else in the country."

He added

"We don't know who to reach at the (U.N.) Security Council to work out the technicalities of the ceasefire. That is the problem at the moment which we are trying to resolve."

4.19pm: A disturbing call from Misrata was just broadcast on al-Jazeera which, assuming the caller was genuine, adds to the evidence that the Libyan regime is not abiding by its announced ceasefire. Mohamed Ali, who said he is at the medical centre, said there has been "indiscriminate shelling" which has wrought, "savagery and destruction on the whole city". He said:

The shelling has been absolutely crazy, absolutely mad, the likes of which in history has never been seen. It's chaotic. I am in the medical centre, I don't know what's happened to my family at home, I don't know if they're still alive.

He then handed the phone over to a doctor who said 80 people were being treated in the hospital.

3.55pm: Yemen's president has declared a state of emergency after "at least 25 protesters" were killed at an anti-government rally, according to Reuters.

The news agency reported President Ali Abdullah Saleh had said armed groups rather than the police were behind the violence.

Reports have suggested Yemeni security forces and unidentified snipers had opened fire on the crowds after Muslim prayers in the capital, Sana'a.

The interior ministry put the death toll at 25, Reuters said, but doctors said 42 people had died and at least 300 were injured. Moh

3.46pm: Ian Black has a little more on the earlier reports of explosions outside Tripoli:

About 10 loud explosions were heard west of Tripoli over about 20 minutes from 1640 to 1700 local time. There has been no official comment or explanation. There was no evidence of any aircraft in the vicinity at the time of the explosions.

3.37pm: My colleague Haroon Siddique has shared this video, which purports to show a demonstration outside a mosque in Homs, in western Syria.

Another video shows a protest said to be in Baniyas in the northwest of the country, while one shows what is said to be Syrian intelligence arresting a man inside the Ummayad mosque in Damscus, one of the holiest Muslim places in the world.

These videos were featured on Enduring America's comprehensive round up of events in Syria today.

3.32pm: Hillary Clinton, providing the first US response, said she had seen the press reports of a ceasefire, my colleague Ewen Macaskill writes.

"It is a fluid and dynamic situation," Clinton said. She added that the US was not looking at what Gaddafi says but deeds on the ground. "We want to see a very clear set of decisions operationalised on the ground by Gaddafi's forces to move a significant distance from the east." She also insisted that Gaddafi would have to leave.

Obama is due to speak on Libya this afternoon.

3.28pm: Ian Black, who is in Tripoli, confirms reports that journalists were prevented from leaving a hotel in the Libyan capital this morning. Ian said the hotel in question acts as a government media centre. He and other journalists were not allowed to leave in what Ian suspects was an attempt to stifle any post-Friday prayers protests from publicity. The media were later escorted out of the hotel on a tour around Tripoli, but were closely watched by Gaddafi forces and limited as to where they could go.

3.10pm: Back to Libya, and Al-Jazeera English is reporting that loud explosions have been heard outside the capital, Tripoli. A correspondent reported hearing a number of large explosions in the past half an hour.

2.57pm – Bahrain: Martin Chulov has spoken to us from Bahrain and describes how the protesters are more determined than ever despite the brutal crackdown this week.

Listen! This is the end of a particularly momentous week in Bahraini life. The streets are utterly abandoned this morning. It's a very eerie scene. People are still seething, there seems to be no resolution at the end of a violent week. People are very determined to press on with the rebellion.

2.48pm – Bahrain: As we're touching on other parts of the Middle East, here is an update from goonerinoman in the comments section in Bahrain.

Just got back from the Pearl Roundabout and the Pearl is no more. I went past it at about 12 Bahrain time and it was there and now having just passed it, I can tell you that it is no more. The Pearl has come down and there are lots of trucks levelling off the ground by the roundabout. Maybe they are going to turn it into a graveyard. It is quite bizarre that whilst there are still some tents up and the rest of the Seef area is a mess to say the least rather than clean the mess of smashed up cars and barbed wire and roadblocks, the government are concentrating their time, money and effort on smashing down and destroying the crime scene. Like any good criminal. Less blockades than normal but lots of tanks and APC.

2.44pm – Syria: There are reports of more demonstrations in Syria today. Malik al-Abdeh, London-based chief editor of the TV channel Barada TV, which campaigns for democracy in Syria, says he has reports of demonstrations in four cities.

Activists have posted a video on Facebook which is said to be of demonstrations in the southern town of Dara, near the border with Israel. This is a Youtube version of the same video, but the quality is poorer.

The Sydney Morning Herald reports on its live blog, quoting the AFP news agency, that plain-clothes police broke up a protest after Friday prayers at the main mosque in central Damascus, dragging away at least two activists."There is no God but God," a crowd inside the men's section of the Omayyed mosque started chanting in crescendo after Friday prayers, it reports.

A number of sources say this is a video of the same event. Our Arbabic-speaking colleague Mona Mahmood says a voice can be heard saying "it's the Omayyed mosque", and others can later be heard shouting "peaceful, peaceful".

2.38pm: This video purports to show Misrata under attack today. Meanwhile, al-Jazeera says Gaddafi troops have struck the Rajban and Zintan areas in the western mountains (via @SultanAlQassemi).

2.34pm: Giles Tremlett in Madrid writes that Spain is an enthusiastic member of the anti-Gaddafi coalition that will enforce the UN resolution.

Socialist prime minister José Luis Rodríguez Zapatero said he had given the US permission to use its military bases in Spain to help enforce a resolution that he called "decisive and historic". Those include both air bases and a naval base at Rota, near the mouth of the Mediterranean, some 1,100 miles from Tripoli. Spain will also provide naval and air assets to the force, though Zapatero said the decision would have to be approved by the country's parliament - which is unlikely to oppose the move. It had not yet been decided exactly what would be needed from Spain. Zapatero, who met UN secretary general Ban Ki-Moon in Madrid today, said the ceasefire announced by Gaddafi was a sign that the UN resolution had already had some impact, but he warned that "the international community will not let itself be fooled by the Libyan regime."

2.31pm: Our colleague, Richard Norton-Taylor, says according to his defence sources no UK jets have taken off yet from their home bases, but that hectic meetings are going on to decide where they will be deployed. Akrotiri in Cyprus is one obvious base.

2.29pm: Philippe Sands, law professor at University College London and a barrister at Matrix Chambers, has welcomed the UN resolution in that it rectifies the damage caused by the Iraq war - albeit with some caveats. Here's an extract.

It is one of those rare occasions in the history of the United Nations in which the use of force has been authorised under Chapter VII... The protracted lessons of Iraq and Afghanistan weigh heavily, and the language of the resolution appears to allow more than only defensive or reactive military measures. And the language precluding any "foreign occupation force" is also ambiguous: it might be interpreted to allow the arming of rebel groups and – to the extent it is requested by those groups – feet on the ground in the form of support that falls short of being characterised as "an occupation force". I welcome the resolution, and strongly so. But inevitably it gives rise to challenging questions: if Libya today, why not Bahrain tomorrow? at what point do such attacks on civilians cross a threshold of unacceptability? what if the attacks are led not by Gaddafi but by an old and trusted ally? These are serious, legitimate questions and they will have to be answered, now that a new door of international action has been opened.

2.19pm: Despite the ceasefire announcement, Gaddafi forces are not only attacking in Misrata but also in Ajdabiya, according to al-Jazeera, which reports "gunfire and heavy artillery clashes" at the southern entrance to the eastern city.

2.15pm: Reuters has a very useful round-up of who might be contributing what to in any military operations against Gaddafi.



France

Likely to deploy Mirage and Rafale fighters from air bases near the Mediterranean towns of Marseille and Istres or from Corsica. Airborne refuelling tanker aircraft are also ready to depart from Istres. Fighter jets could reach Libya in around an hour and a half from the south of France and in around an hour from Corsica. The Charles de Gaulle aircraft carrier is in Toulon so would be ready to deploy fast.

Britain

Britain said it would deploy Typhoon patrol jets and all-weather Tornado attack aircraft based at RAF bases in Scotland and in Norfolk but would be moved to unidentified bases nearer Libya. Britain has two frigates if needed off the Libyan coast: HMS Cumberland and HMS Westminster.



United States

The US navy has an aircraft carrier, the USS Enterprise, and other warships in the Mediterranean, but unclear whether they would be used.

Italy

Italy is unlikely to take part in strikes but is expected to provide its air base at Sigonella in Sicily. Fighter jets leaving from Sicily could reach Libya in around half an hour.

Norway

Norway said it will make its F-16 fighter jets available for an operation in Libya and could also provide Hercules transport aircraft to assist in humanitarian efforts.

Denmark

Denmark said it would send six F-16 planes and one military transport plane to support an intervention in Libya. The planes were ready to leave Denmark on Saturday for a southern European base with around 100 personnel including pilots and support.

Reuters says Saudi Arabia, the United Arab Emirates and Qatar are seen as the most likely Arab nations to provide back-up for an operation.

2.04pm: Here's more from Owen Bowcott's q&a on the legal aspects of military intervention.

Q: Which targets can be attacked?

A: Even though the resolution establishes a 'no-fly zone', Gaddafi's airfields, anti-aircraft batteries, command centres in Tripoli and grounds forces assaulting rebel strongholds could all come under bombardment from allied forces. Libyan troops engaged in battles with rebel fighters, for example around an arms dump, would not technically be at risk because the resolution specifies protecting only civilians. "This will involve bombing Libyan airfields and air defences," said Richard Piotrowicz, professor of international law at Aberyswyth university. "It does not mean they only attack aircraft in the air. However it would not justify French or British aircraft destroying Libyan forces just for the sake of it."

Q: Does it matter that five states abstained in the UN security council vote? Is the wording of the resolution open to rival interpretations?

A: The fact that Russia and China chose not to use a veto sends a clear signal of tacit political approval. "Sometimes these UN resolutions are not clear," explained Anthony Aust, a former Foreign Office legal adviser who helped draft the Kuwait resolution in 1990. "They are ambiguous because it's the only way to avoid a veto." The authority for military action is immediate. A ceasefire by Gaddafi's forces, however, will be used to challenge the justification for allied air strikes.

2.01pm: David Cameron says Gaddafi will be judged by his deeds not words when asked about the ceasefire. He told BBC TV.

We will judge him by his actions not his words. What is absolutely clear is the UN security council resolution said he must stop what he is doing, brutalising his people. If not, all necessary measures can follow to make him stop. That is what we agreed last night, that is what we are preparing for and we'll judge him by what he does.

1.57pm: Our colleague Owen Bowcott has been talking to legal experts about the legal aspects of military intervention in Libya. Here is the first part of his q&a.

Q: What does the UN resolution permit the participating allies to attack?

A: The security council vote gives wide-ranging authorisation for the use of force against targets in the air and on the ground, according to most international lawyers. The phrase in paragraph 4 of Resolution 1973 calls on member states "to take all necessary measures ..... to protect civilians and civilian populated areas under threat of attack..." Malcolm Shaw, professor of international law at Leicester university, described it as giving the broadest powers for intervention since the UN resolution deploring the Iraqi invasion of Kuwait in 1990.



Q: Can UN-backed forces put anyone on the ground?

A: Ground spotters to improve the accuracy of air strikes might even be allowed under the terms of the resolution which explicitly excludes "a foreign occupation force of any form on any part of Libyan territory", some lawyers suggested. If the intention is not to occupy, then their presence could be deemed not to conflict with the UN's aims. "Some supportive ground presence would be authorised," Professor Shaw said.

1.53pm: There are doubts already about whether Gaddafi's forces are observing his promised ceasefire. The Associated Press and Al Arabiya TV report that the city of Misrata is still being shelled by Libyan troops. Twenty-five people are reported dead.

"Gaddafi's forces are bombing the city with artillery shells and tanks. We now have 25 people dead at the hospital, including several little girls," a doctor said by satellite phone.

1.49pm: At the end other end of Libya, in Benghazi, Chris McGreal says the rebels do not plan to give up the fight against Gaddafi despite his declaration of an immediate ceasefire.

The rebels say they don't trust Gaddafi. They see it as a reflection of his desperation to try and stave off the air attacks by France and Britain and that what he intends to do is to divide up the country and for that reason they are not going to call a ceasefire themselves. They plan to call for uprisings across the country to get rid of Gaddafi.

1.37pm: The New York Times is reporting that four of its journalists captured in Libya will be released.

The journalists are Anthony Shadid, Beirut bureau chief for the NYT; two photographers, Tyler Hicks and Lindsey Addario; and reporter Stephen Farrell, who holds dual British and Irish nationality.

Gaddafi's son Saif told ABC's Christiane Amanpour in an interview recorded yesterday tthat Addario would be released. The NYT said that Libyan government officials told the US state department on Thursday evening that all four would be freed.

It is not clear whether the vote at the UN security council in favour of a no-fly zone over Libya, supported by the US, would have any effect on the decision to release the journalists.

1.18pm: Ian Black in Tripoli has some instant analysis of the ceasefire declaration.

The Libyan announcement of a unilateral ceasefire made by foreign minister Moussa Koussa leaves several important questions unanswered. Is it simply a ploy to divide the UN after the approval of the security council resolution? And how will a ceasefire be monitored and verified? Will the UN be allowed in? Fighting was reported from the port of Misrata shortly before his press conference in Tripoli. His offer of dialogue has already been rejected by the Benghazi-based rebels. The Gaddafi regime is pretty low on credibility so there will be plenty of scepticism about this statement. And Koussa pointedly refused to answer any questions after dropping his bombshell.

1.09pm: On a lighter note. Malta's tourism authority is keen to correct what it says is incorrect information in parts of the British media.

Please be aware that there are NO British military bases in Malta, emails the Malta Tourism Authority. Two news sources - Sky News and Metro, have erroneously stated that British Military bases in Malta could be a possible target for Libyan counter attacks, Please be aware that this is false and that Malta has no British military bases and is not a target.

12.54pm: Libya has declared "an immediate ceasefire", but has criticised the UN resolution, saying the use of military power would "violate" the UN charter. Here's a summary, including details of the statement from the Libyan government:

• Moussa Koussa, the Libyan foreign minister, announced that the country had decided to call a ceasefire, announcing the the "stoppage of all military operations" at a press conference in Tripoli. Koussa said the country has studied the UN resolution, and as a security council member it would accept the resolution. He said Libya encourages the "opening of all dialogue channels" with the international community.

• Despite this, Koussa criticised the ruling, saying it was "unreasonable" that it allowed the use of military power. He said the use of military power would violate the UN charter and violate the sovereignty of Libya. He added that the UN resolution would "increase the suffering of the Libyan people", while the freezing of Libya's assets would have a "very negative impact on normal Libyans".

• On Thursday night the security council voted in favour of a no-fly zone and air strikes against Muammar Gaddafi's forces. Resolution 1973 authorises "all necessary measures" short of a ground invasion to protect civilians in Libya.

• Before the ceasefire was announced, the British prime minister, David Cameron, said RAF Tornados and Typhoons would be deployed in the operation. They will be moved to air bases "in the coming hours", Cameron told the House of Commons in London. He said: "The attorney general has been consulted and the government is satisfied that there is a clear and unequivocal legal basis for the deployment of UK forces and military assets."

12.46pm: Koussa steps up his offensive: Libya also finds it "unreasonable" that the resolution allows the use of military power.

"There are signs that this might indeed take place," he said.

"This goes clearly against the UN charter, and it is a violation of the national sovereignty of Libya.

"It is also a violation of article 42 of the charter."

12.43pm: A change in tone from Koussa, as he criticises the UN resolution: "My country is very serious about continuing the development – economic, social of the Libyan nation," Koussa says.

"We express our sadness towards what the resolution has included, and of procedures against the Libyan nation, such as the no-fly zone", Koussa says. He said the inclusion of commercial flights will "increase the suffering of Libyan people", and says the international community should have exempted these flights from the resolution.

"Also the total and inclusive freezing of all Libyan assets and investments will have a very negative impact on normal Libyans," the foreign minister says.

12.40pm: Koussa continues to stress that Libya's actions are done in accordance with the UN's resolution.

"We agree to the article on the protection of civilians," he says.

"Therefore, building on this, the Libyan state encourages the opening of all dialogue channels with everyone interested in the territory of Libya."

12.38pm: "Libya has decided an immediate ceasefire and stoppage of all military operations," the country's foreign minister Mousa Koussa says.

12.36pm: Koussa says that Libya has studied the resolution.

"MY country will try to deal with this resolution," Koussa says.

"Libya has now got knowledge of the resolution, and in accordance with article 25 of the UN charter and given that Libya is a member of the UN security council, Libya is committed to accept the UN security council resolution."

12.34pm: The Libyan foreign minister, Moussa Koussa, is preparing to speak to journalists in Tripoli. We'll follow it live.

12.18pm: More from Nick Watt in the House of Commons, where Mark Reckless, a Conservative backbencher, has "asked the awkward question of the day".

Reckless asked the prime minister whether the operation would be better if Ark Royal, equipped with Harrier aircraft, could take part. The aircraft carrier was decommissioned as part of the strategic defence and security review last year. Hilary Benn, the shadow leader of the commons, welcomed the decision to hold a debate on the military action on a substantive motion, followed by a vote on Monday. Benn pointed out that it is exactly eight years ago to the day since MPs voted to approve the Iraq war. Jack Straw, the foreign secretary at the time, set a precedent by giving MPs a vote on a substantive motion. Until then debates about British military action were technically adjournment debates. This meant the only vote MPs could hold was on whether to adjourn the house.

12.12pm – Yemen: While the prime minister has been speaking about the planned military action in Libya, there have been disturbing events in Yemen, where citizens in Sana'a have been shot dead.

The Guardian's Tom Finn is at a mosque in the city, and says he has counted 17 dead people being brought into the building wrapped in blankets. "The doctor says [there are] double that in the hospital," Tom tweets.

Al-Jazeera English is reporting that up to 30 people have been killed and 200 injured after security forces opened fire in Sana'a.

12.07pm: Our colleague, Ian Black, who is in Tripoli, says Muammar Gaddafi is far from cowed by last night's vote at the UN, although there is a mood of nervousness in the city as well as defiance:

Listen! Gaddafi was pretty defiant from the start, he gave an interview to Portuguese TV just as the vote was about to take place and it was clear at that stage it was going to produce a no-fly zone and he was very ominous. He was talking about how the world goes crazy, we'll go crazy too... He was menacing about and to the people of Benghazi. He said there would be no mercy, no pity. If you were a rebel in Benghazi you could be forgiven for feeling quite anxious.

12.03pm: The Guardian's chief political correspondent, Nick Watt, has been following the questions to Cameron in the Commons following the prime minister's statement.

Nick says there is "strong praise" for Cameron from both sides of the House, "though some Labour MPs are voicing doubts".

James Arbuthnot, the Tory chairman of the commons defence select committee, said the prime minister has shown a "breathtaking degree of courage and leadership". Mike Gapes, the former Labour chairman of the commons foreign affairs select committee, congratulated Cameron, British diplomats at the UN and the French government. But Jeremy Corbyn, the veteran left winger, asked why action was being taken to protect human rights in Libya while no action was being taken in Saudi Arabia and Bahrain. Natascha Engel, a Labour MP, questioned whether the air strikes would compound a difficult situation. David Winnick, a veteran Labour MP, warned that Britain could be dragged into a third war in ten years. Nicolas Sarkozy has invited members of the Arab League to a meeting in Paris on Saturday. David Cameron will attend.

Nick says that David Cameron has told MPs that the government will publish a summary of the legal advice by Dominic Grieve, the attorney general, which has given formal approval for British participation in Libya.

"This will be published before a commons debate on Monday when MPs will vote on the military action," Nick says. "In another departure with Tony Blair's approach over the Iraq war in 2003, the prime minister announced that the international development secretary Andrew Mitchell is to chair a cross-Whitehall group to coordinate humanitarian efforts in Libya."

12 noon: Welcome to the Guardian's continuing coverage of the crisis in Libya as the UN backs military action and the British government commits RAF jets to the operation. You can find our earlier coverage here.

Here are the main points of the story so far:

British and French military aircraft are preparing to protect the Libyan rebel stronghold of Benghazi after the UN security council voted in favour of a no-fly zone and air strikes against Muammar Gaddafi's forces. Resolution 1973 authorises "all necessary measures" short of a ground invasion to protect civilians in Libya.

The British prime minister, David Cameron, said RAF Tornados and Typhoons would be deployed in the operation. They will be moved to air bases "in the coming hours", Cameron told the House of Commons in London. He said: "The attorney general has been consulted and the government is satisfied that there is a clear and unequivocal legal basis for the deployment of UK forces and military assets."

Gaddafi has warned that any foreign attack on Libya would endanger air and maritime traffic in the Mediterranean area. In a defiant and menacing radio address on Thursday night, the Libyan leader sald. "No more fear, no more hesitation, the moment of truth has come. There will be no mercy. Our troops will be coming to Benghazi tonight."