11.39pm GMT: It's time to wrap this live blog up for the night. Here's a summary of the most recent events:

• Fighting continues in the key coastal towns in Libya, with both sides claiming victory after a heavy battle in Zawiyah. Rebel forces said they held the town as night fell, with pro-Gaddafi forces withdrawing

• Aerial attacks by Libyan air force planes on oil refining facilities near Ras Lanuf caused an unknown number of deaths and injuries

• BBC staff were arrested and beaten by members of Gaddafi's security forces, it was revealed

• The Gaddafi regime embarked on a diplomatic offensive, sending envoys to Egypt and Europe, while representatives from the opposition National Transitional Council met with Swiss government leaders

• The White House said it was considering further options, including the sale of weapons to opposition forces in Libya

• A house in the London suburb of Hampstead, identified as belonging to the Gaddafi family, was occupied by protesters

• Protests continued in Yemen after violent clashes on Tuesday night

• Morocco's King Mohamed VI offered a series of political reforms including a referendum on constitutional changes, greater freedom for political parties and a freely elected parliament and prime minister. Opposition groups largely welcomed the offer

Thanks for reading. The Guardian's regular news coverage continues here.

11.14pm GMT: Reuters reports from Marrakesh on the plans for sweeping constitutional change announced tonight by Morocco's King Mohamed:

Morocco is officially a constitutional monarchy with an elected parliament. But the constitution empowers the king to dissolve the legislature, impose a state of emergency and have a key say in government appointments including the prime minister. The monarch said the reform would make the judiciary independent, have a freely elected parliament with new powers, a government elected by parliament, a prime minister from the majority party and greater powers for political parties. "The institutions concerned with good governance, human rights and protection of liberties" would be enshrined in the constitution, he said. Saeed Binjebli, an organiser of the youth-led movement for change, said the speech should limit protests in the short-term but social woes could fuel more protests. "This was a very bold speech," he said. "The king responded favourably to all our demands on the constitutional front."

10.55pm GMT: Meanwhile, Saudi Arabia remains unruffled by the turmoil in the region. Here's an excellent piece by Neela Banerjee in the Los Angeles Times, reporting from Riyadh on a meeting of the kingdom's dissidents:

The guest of honor was a 40-year-old university professor named Mohammed Abdulkarim, who had just returned from 10 weeks in solitary confinement for a post to his Facebook page about a succession struggle in the Saudi royal family. The 60 or so lawyers, doctors, academics and clerics feting him are the leading opposition voices in Saudi Arabia. Many have been imprisoned, some several times, often for seemingly mild acts of protest such as letters, petitions and calls to the foreign press.

10.45pm GMT: The Associated Press has excellent coverage of events in Yemen after last night's violent attacks on protesters:

Outraged at the government raid, more protesters camped out in tents near the university and on campus Wednesday. A group of young protesters issued a "black list" with the names of 13 officials they say are responsible for the violence against peaceful protesters. The names include the son of President Ali Abdullah Saleh who heads the Republican Guards, the interior minister and other top security officials. The statement vowed revenge against those they called "criminals" and pledged to continue with the sit-in until they topple the regime. Thousands of people also protested in the southern port city of Aden and on the streets of Ibb province.

10.41pm GMT: From Egypt comes the unsurprising news that Mohamed ElBaradei intends to run for president in Egypt's 2011 presidential election.

"When the door of presidential nominations opens, I intend to nominate myself," ElBaradei told ONTV.

10.26pm GMT: The Guardian's Giles Tremlett in Madrid gives his analysis of the constitutional reforms being offered by Morocco's King Mohamed live on television tonight:

King Mohamed VI of Morocco looks like he wants to stay a step ahead of the Arab revolutions. He has announced a constitutional reform process with moves towards a parliamentary monarchy system, giving up the power to appoint the PM to the parliament itself (rather than the monarch). That's quite a big change. We will have to see how far this goes, but the steps are obviously in the right direction. They key question will be how much power the monarch is prepared to give up.

10.15pm GMT: The three BBC journalists arrested in Libya were held for 21 hours en route to Zawiyah to report on the fighting there. BBC News reports:

One of the team, Chris Cobb-Smith, said: "We were lined up against the wall. I was the last in line - facing the wall. "I looked and I saw a plain-clothes guy with a small sub-machine gun. He put it to everyone's neck. I saw him and he screamed at me. "Then he walked up to me put the gun to my neck and pulled the trigger, twice, the bullets whisked past my ear. The soldiers just laughed." A second member of the team - Feras Killani, a correspondent of Palestinian descent - is said to have been singled out by their captors for the worst of the violence. The third member of the team, cameraman Goktay Koraltan, said he was convinced they were going to die.

9.46pm GMT: Two BBC journalists in Libya say they were tortured and subjected to a mock execution by members of Gaddafi's regime, it has been revealed.

The Guardian's Peter Beaumont reports from Tripoli:

The shocking account of their experiences, including being held in a cage in a militia barracks while others were tortured around them, was made available to media colleagues in Tripoli after the men had been released and left the country. At one point during their captivity the men had shots fired past their heads as they were led into a barracks. One of the men was attacked repeatedly with fists, boots, rifle butts, a stick and piece of pipe. He also described trying to help other victims of torture whom they saw, some of whom had had their ribs broken during beatings.

9.39pm GMT: Some news from Morocco, where King Mohamed has just given a gnomic television address to the nation in which he appears to have announced plans for a constitution and a referendum.

"By launching today the work of constitutional reform, we embark on a major phase in the process of consolidation of our model of democracy and development," the king said, wearing glasses, a dark suit and tie.

The king also said the reforms would include an independent judicial system, autonomy for political parties and plans to grant more powers to local officials and politicians.

It's not entirely clear what the implications of all this will be, but the headline news is that Morocco's king is voluntarily giving up some of his power.

9.20pm GMT: The Wall Street Journal tries to explain where the White House is on the matter of arming rebels in Libya with an arms embargo in place:

Administration officials said there is no need to reinterpret the UN resolution, since it establishes a sanctions committee that can issue waivers, including to arm rebel groups. Such a waiver, officials said, would only be sought after an international consensus develops on the best way to aid the Libyan opposition.

9.06pm GMT: Al-Jazeera manages to talk to fighters near Ras Lanuf, who speak of a large number of injured after bombing by air force jets. "Right now we are collecting the dead and wounded. We are collecting body parts," the unidentified fighter said.

While supplies were reaching the town from the east, the attacks have knocked out the water plant near Ras Lanuf, meaning that drinking water was scarce.

The same fighter said that the rebels were keen to attack deeper into Bin Jawad but that they are approaching cautiously because Gaddafi's forces are said to be holding families as human shields.

8.44pm GMT: With no clear sign that the Nato countries will approve a "no-fly zone" over Libya, rebel leaders are threatening to take matters into their own hands.

According to AP, a rebel spokesman said today that the opposition will buy weapons if the international community fails to declare a no-fly zone:

"If a no-fly zone is not imposed, we do have the means to get armaments. We don't expect any country to refuse to deal with us in terms of an arms sale," said Abdel-Hafidh Ghoga, a spokesman for the rebels' provisional transitional national council. He did not elaborate or say where the rebels would get the money for arms.

Earlier, the White House appeared to confirm that the arms embargo against the Gaddafi government would still allow the sale of arms to the opposition.

Jay Carney said today: "We believe that the arms embargo contains within it the flexibility to allow for a decision to arm the opposition, if that decision were made."

8.30pm GMT: Bloggers at Foreign Policy magazine have got hold of an off-the-record conference call between the White House and NGOs, revealing that Washington is trying to stem the flow of mercenaries into Libya:

Though the Obama administration hasn't yet decided whether or how to aid the Libyan opposition, the White House is working to stop the flow of mercenaries fighting for Qaddafi entering the country from countries surrounding Libya like Chad and Niger. "We've been working to ensure there isn't a flow of people into Libya," said Samantha Power, the National Security Council's senior director for multilateral affairs, on a Wednesday conference call with non-governmental groups. The call was off the record, but a recording was provided to The Cable. Power didn't go into detail about whether or not the administration believes that Qaddafi is still trying to import mercenaries and she didn't going into detail about what the U.S. was doing to stop the flow of people into Libya. Power was responding to a question about what the White House was doing to make sure violence in Libya didn't spill over into other countries, such as Sudan. She responded that the White House was monitoring the flow of migrant workers as well as those who might be coming to Libya to fight in the conflict.

8.17pm GMT: The Guardian's Chris McGreal reports from Benghazi on the fatalism among opposition supporters there in their struggle to overthrow the Gaddafi regime:

Fears are growing that if Gaddafi wins in Zawiyah, he will then redirect the scores of tanks and armoured vehicles used there against the rebels in the east. Some in Benghazi have fallen back on a grim fatalism. Gebril, whose parents have both served time in Gaddafi's prisons for opposing his regime, says that excitement at the prospect of the dictator's downfall has given way to a realisation that she may be forced to flee the country. "If he wins, we're dead. He will kill us. Before is nothing compared to what he would do now. The whole of the east side of the country is dead. I would get out. I'm still young. I've got to live."

8.02pm GMT: The fighting in Libya has disrupted a joint UK-US sponsored programme designed to keep about hundreds of Libyan nuclear and chemical weapons experts busy on civilian projects and prevent them from selling their expertise to other countries, the Associated Press reports in an exclusive:

After Libya agreed to give up its weapons of mass destruction in 2003, the US has been spending about $2m a year to steer weapons scientists and technicians into other fields, including medicine, green technology and the oil and gas industry, current and former US officials told the AP. Efforts by the US and by Britain, which also is involved in the programme, have helped build a seawater desalination plant, a water quality lab and a telemedicine facility at the Tripoli Medical Center. About 200 nuclear specialists and 500 others who worked with chemical weapons and missile technology could be driven to leave Libya by the fighting, including key figures in the nuclear weapons programs. "If they're facing an uncertain future, they may just walk," said Sharon Squassoni, an arms control specialist at the Carnegie Endowment for International Peace.

7.47pm GMT: The private planes that flew out of Tripoli earlier today have turned out to be part of the new diplomatic offensive on the part of the Gaddafi regime.

One flight went to Cairo, carrying a private message from Gaddafi to Egypt's military leaders, another flight went on to Lisbon, and a third to Brussels, via Paris, ahead of a pair of crucial meetings in Brussels, including the EU foreign ministers meeting.

In Portugal foreign minister Luis Amado met with an unidentified envoy from Gaddafi's government at a hotel in Lisbon, in what was described as an informal meeting "to discuss the upheaval in Libya" in a statement:

O ministro de Estado e dos Negócios Estrangeiros, Luís Amado, aceitou encontrar-se hoje em Lisboa com um emissário líbio, a pedido deste, a fim de receber informações sobre a situação que se vive na Líbia.

7.32pm GMT: More details are coming in from the rebel fighters who appear to have retaken control of the centre of Zawiyah this evening.

Reuters has spoken to an anti-government fighter in the city named Ibrahim:

"We have pushed [pro-Gaddafi forces] out and we are back in the square now," Ibrahim said by telephone. "They are one kilometre away now. Thanks to Allah we are sitting in the square now." The civilians, who were not from Zawiyah, had chanted pro-Gaddafi slogans, he said. Libyan television had earlier shown a loyalist crowd in the city. "There is no fighting at the moment, but if the fighting begins, those civilians will be caught between the fire," he said, adding that the Gaddafi forces had left a trail of destruction on their way into Zawiyah. "This is a death or life battle for us, we have nothing to do now but to fight [Gaddafi]," Ibrahim said. He added: "We are running out of food and baby milk. This is a disaster for us. As adults we can bear it without food but babies do not understand and they are crying."

7.15pm GMT: Reuters is quoting a rebel fighter in Zawiyah as saying the opposition forces had retaken the main square of the city tonight after pro-Gaddafi forces took control of it earlier in the day but later pulled back to the outskirts.

The fighter named Ibrahim told Reuters the government had brought in supporters of Gaddafi for a rally in the centre, who were now caught between rebel and loyalist forces, but that there was currently no fighting in the city.

7.01pm GMT: The fighting in and around the Libyan town of Zawiyah remains a see-sawing battle between pro-Gaddafi and anti-government forces.

For example: Reuters reported at 6.48pm GMT: "Gaddafi's forces regain control of Zawiyah centre". Then at 6.56pm GMT, the agency sent out another news flash: "Zawiyah fighter says rebels have retaken main square, Gaddafi forces now one km outside city".

In the 19th century this is what was called "the fog of war".

6.46pm GMT: The UK's Sky News is citing a report by AFP from "rebel medics" in Benghazi, who say that at least 400 people have died in the east of Libya since the uprising began.

6.38pm GMT: In Yemen there are further reports of clashes between government loyalists and protesters in Hadr Maut, in the south of the country.

6.26pm GMT: With opposition forces in eastern Libya under increasing pressure from the Gaddafi regime's sophisticated weaponry, the White House says President Obama has called a top-level meeting of his security advisors to discuss Libya.

The White House's press secretary Jay Carney says the president has the meeting scheduled for later this afternoon to "review events in Libya and assess steps that have already been taken," as well as considering the remaining options for the US government.

6.18pm GMT: Libya's National Transitional Council now has a website that it launched today, in both English and Arabic:

The council derives it legitimacy from the decisions of local councils set up by the revolutionary people of Libya on the 17th of February. These local councils facilitated a mechanism to manage daily life in the liberated cities and villages. The council consists of thirty one members representing the various cities of Libya from the east to the west and from the north to the south. The aim of the Transitional National Council is to steer Libya during the interim period that will come after its complete liberation. It will guide the country to free elections and the establishment of a constitution for Libya.

6.12pm GMT: The Libyan opposition may be losing ground on the battlefield but it appears to be making some progress on the diplomatic front.

Switzerland's federal president Micheline Calmy-Rey met with a delegate from Libya's opposition National Transitional Council – and thanks to reader Michael Bimmler for spotting and translating this statement from the Swiss government:

Federal President Micheline Calmy-Rey, head of the federal department of foreign affairs, has today received a representative of the national Libyan transition council for a discussion. Jebril el-Waalfarvi explained the current situation and potential developments in Libya from his point of view to the foreign minister during the meeting. Federal president Calmy-Rey was during the discussion especially worried about the difficult position of the Libyan civilian population which is subject to "targeted and despicable violence by the responsible persons in Libya". Switzerland will "leave no stone unturned" in order to support the civilian victims of the civil war with diplomatic and humanitarian means.

5.54pm GMT: Libyan state television is now broadcasting images of Zawiyah apparently firmly in the hands of the pro-Gaddafi government forces.

The images appear to show a crowd of several hundred people in Zawiyah, with many waving green flags and carrying images of Gaddafi, chanting: "We want Colonel Gaddafi!".

5.40pm GMT: According to al-Arabiya television, an eyewitness in Zawiyah is reporting another round of heavy bombardment on the town this evening, which may herald a further assault by Gaddafi's armed forces

5.21pm GMT: The Guardian's Esther Addley reports from the front lines of Hampstead in London, where the struggle against the Gaddafi regime takes on a very British form – squatting:

I'm just back from an occupation of Saif Gadaffi's house in Hampstead, which has been occupied by a group calling themselves Topple the Tyrants. It's a redbrick house in a small close, rather disappointing for a tyrant dynasty but apparently it's worth £10m. There aren't too many of the group, it's not clear exactly how many there are, and they've put up a few banners on the roof. We had a photographer there so there will be photos soon.

This house is presumably the one where Saif Gaddafi spent so many days writing his London School of Economics PhD thesis.

5pm GMT: With all the events going on in North Africa and the Middle East, here's a brief country-by-country summary, thanks to Reuters:

Libya

Gaddafi's forces are said to have entered the main square of the rebel stronghold of Zawiyah on Wednesday, while rebel forces advances along the strategic coastal road towards from Ras Lanuf towards Gaddafi's home town of Sirte have been fought off

Yemen

President Saleh is resisting demands for his resignation, with opposition supporters vowing to continue their protests after police and security forces fired on a group in front of Sanaa University. Some 30 people are said to have died since the protests began.

Saudi Arabia

Saudi Arabia's foreign minister Prince Saud al-Faisal has called for talks rather than protests, as even Saudi Arabia's huge wealth has proved to be no guarantee of tranquility in the face of discontent from the country's Shia minority.

Kuwait

The oil-rich country saw several hundred people gather in a car park they named "The Square of Change" this week, and call for Sheikh Nasser al-Mohammad al-Sabah, a member of the ruling family, to step down as prime minister, as well as demands for greater political freedom.

Tunisia

A court in Tunisia has ruled that the political party of former President Ben Ali must be dissolved, triggering street celebrations as one of the last vestiges of the ousted leader's era was dismantled.

4.45pm GMT: The Associated Press has more on the occupation of Seif Gaddafi's alleged mansion in Hampstead Gardens Suburbs:

A group calling itself Topple the Tyrants said its members entered the house in solidarity with Libyans trying to oust the Gaddafi regime. Several climbed onto the roof and unfurled a banner showing Gaddafi's face and the words "out of Libya, out of London." Spokesman Montgomery Jones said the squatters, who are not Libyan, would stay "until this property can be returned to the Libyan people." "We don't trust the British government to return the house to the Libyan people, to whom it rightfully belongs," he said. He said the group hoped Libyan exiles would come join them at the eight-bedroom Georgian-style house, which has a swimming-pool, hot tub and sauna The house is reportedly owned by Seif al-Islam Gaddafi, a graduate of the London School of Economics. It had been on the market for more than £10m ($16m), but was withdrawn from sale last month. The Metropolitan Police said officers were monitoring the situation and no arrests had been made. The force said it was treating the occupation "as a civil matter."

The Guardian's Esther Addley is on the scene, and we hope to have a report live from the front line in Hampstead shortly.

4.30pm GMT: Good afternoon, here's an summary of events in Libya earlier today:

• Gaddafi's tanks have reportedly been moving towards the centre of Zawayiah, held by opposition forces.

• There have been a fresh airstrikes on the eastern oil town of Ras Lanuf, al-Jazeera has reported.

• Three of Gaddafi's private jets have reportedly headed to Cairo. AP said a high-ranking member of the Libyan government was carrying a message from Gaddafi

• The UN's special rapporteur for torture has opened a probe into allegations of torture used by Gaddafi's forces since the beginning of the uprising.

• Gaddafi has accused western powers of trying to get their hands on Libya's oil and wealth.

This is Richard Adams in the Guardian's Washington bureau, following all the events in Libya and elsewhere in the region.

You can catch up on our earlier coverage here.