Several people have been injured in a large explosion which has damaged government buildings in central Oslo, including the office of the Norwegian prime minster.

A Reuters correspondent said he counted at least eight injured people after the unexplained blast.

The tangled wreckage of a car was outside one building but the cause of the blast was unknown with police and fire officials refusing to comment.

The explosion at around 3.30pm (2.30pm BST) blew out most windows on the 17-storey building housing prime minister Jens Stoltenberg's office, as well as nearby ministries including the oil ministry, which was on fire. Norwegian news agency NTB said the prime minister is safe. Newspaper offices in the area were also reportedly damaged.

The city centre - which usually empties in July as Norwegians take holidays - is currently closed off with all public transport to and from the centre suspended.

A Norwegian reporter told the BBC she is in a buidling five blocks away and its windows have been blown out by the explosion. She used the word "bomb" before clarifying that she had no evidence the cause of the explosion was a bomb but suggested that she could not see what else would cause an explosion of such magnitued.

This video shows windows blown out and people walking over pavements covered in shattered glass.

NRK, the Norwegian broadcaster, says that one person has been killed, Lars Eriksen in Denmark informs me.

Senior adviser Oivind Ostang told Norwegian TV2.

We can confirm that everybody who was working in the prime minister's office today are safe. The only thing I know is that there has been a fire or something approaching a fire in the R4-buildling which houses the oil- and energy office.

Here's another video showing the extent of the devastation wreaked by the explosion

An Icelandic MP has tweeted that seven people have been admitted to hospital in Oslo.

Eyewitnesses say there are many ambulances on the scene.

Mike Emery, working in Norway for a charity, emailed me:

According to NRK (Norwegian public service broadcaster) there is broken glass up to 1km from the blast site. July is the holiday month in Norway and almost everyone goes on vacation. We have to hope that many people are on holiday. The blast happened after 3.15pm and Norway is on Summer Working Hours meaning people leave work at 3pm. Let's hope this is the case.

ABC News reports that the "was [the] result of a massive vehicle bomb, according to US government sources on the scene".

Swedish reporter Carl Kleberg has tweeted this:



Police stops reporter of #Norway's Aftenposten: "because there are still two bombs that we don't know where they are." #Oslo

Oslo police have said the explosion was caused by a bomb, the BBC just said.

Oslo police also referred to "deaths and injuries" but did not specify numbers. So far one person has been confirmed dead as a result of the explosion, which police now say was caused by a bomb.

The Norwegian state broadcaster now says two people are confirmed dead.

Peter Beaumont, foreign affairs editor at the Observer, says a jihadist group is most likely to be behind the blast:

It has been known for some time that al-Qaida core and other related "franchises" - including in the most active in Yemen – have been attempting to develop operations. Which leads to a second question: why Norway?... The answer to that is three fold. In then first instance, with the increased levels of security and surveillance in the UK and the US as well as other European capitals, Norway might have been seen as a softer target despite the recent breaking up of an al-Qaida cell in Norway. A more detailed explanation of the problems that Norway has had with Al Qaeda were supplied a year ago by the Atlantic magazine in an article by Thomas Hegghammer, a senior fellow at the Norwegian Defence Research Establishment in Oslo, and Dominic Tierney. That piece followed the arrest of three men in Norway and Germany for allegedly plotting a terrorist attack involving peroxide explosives. All of those arrested were were Muslim immigrants to Norway. The first explanation," wrote Hegghammer and Tierney, "is Afghanistan. Norway has been part of the International Security Assistance Force (ISAF) in Afghanistan from its foundation in late 2001.... In late 2007, for example, Ayman al-Zawahiri, al-Qaida's

second-in-command, said that the group had previously threatened Norway because it "participated in the war against the Muslims... A second contributory factor for why Norway may have been eyed in the past for potential jihadi terrorist attack is the fact that in 2006, a Norwegian newspaper reprinted a series of Danish cartoons depicting the Prophet Muhammad which prompted threats against the country. A third potential explanation is the recent decision last week by a Norwegian prosecutor filed terror charges against an Iraqi-born cleric for threatening Norwegian politicians with death if he's deported from the Nordic country. The indictment centered on statements that Mullah Krekar - the founder of the Kurdish Islamist group Ansar al-Islam - made to various media, including American network NBC.

According to reports from the newspaper Dagsbladet, the bomb was meant to target the office of the oil and energy ministry, Lars Eriksen in Demark informs me.

Rumours have been rife of additional bombs (possibly two more) in Oslo.

NRK (the state broadcaster) is saying police believe there are no more bombs.

But Nicholas Karlsen in Oslo emailed me to say that Aftenposten newspaper is reporting police believe it is possible there two more bombs that they haven't located yet.

The police have said on NRK that there are more dead (and injured) inside the buildings, Neil Perry, a former Guardian colleague, now living in Oslo informs me.

Also, Norway government official Hans Kristian Amundsen told the BBC that there are people trapped at bomb site

Neil said officers say there are quite a few injured inside the affected buildings who have

called police on their mobiles to let them know they are inside.

Neil also shared his own reaction when the bomb went off:

I live in Vålerenga, which is about a 15-minute bus journey from the city centre. It was loud even where I was, I jumped and initially thought it was thunder. Then I saw a large white cloud of smoke rising in the distance.

The official police statement says:

There has been one or several powerful explosions in the government district in Oslo. So far, police cannot say anything about the scope of the damage, aside from that there's been one or several explosions.

The BBC says police have told them it is believed to be terrorism-related although they do not no the motive.

The official police statement says:

There has been one or several powerful explosions in the government district in Oslo. So far, police cannot say anything about the scope of the damage, aside from that there's been one or several explosions.

The BBC says police have told them it is believed to be terrorism-related although they do not no the motive.

Police are now saying 15 people are confirmed injured, says the BBC.

They are telling people to leave the centre of Oslo and warning there could be more explosions.

They are also examining an unexploded package, although the location of the package is not clear.

Neil Perry in Oslo just sent me this worrying development. I'll try to get more details:

A man disguised as a police officer began shooting where youth were attending a Labour party conference at Utøya, Prime Minister Jens Stoltenberg has just confirmed. He said there is a 'critical and serious situation' but he is safe. He was speaking on the phone to Norwegian TV station TV2.

UPDATE: This post was amended as Stoltenberg was not present at the conference as previously stated. He had been due to attend it but did not go.

Neil Perry has sent me more details of the shooting on the Labour party youth camp, which suggests the possibility of co-ordinated attacks. It is a Google translation from Dagbladet, tidied up a bit, so it is not perfect.

yewitnesses told the AP that a man dressed as a police officer has fired several shots at Utøya in Buskerud. AP spoke with one of those who were on Utøya where there is an AUF event with over 700 people. "Suddenly, we heard lots of shooting. People had to run and hide. We have been told to get off the island." "We now have reports of a serious situation there - a critical situation on Utøya," Prime Minister Jens Stoltenberg told TV 2 The police are now on site and sealed off the area. Bjorn Jarle Røberg-Larsen of Labor, is not in Utøya, but has had telephone contact with young people who are on the island. "They say that at least one person wearing a police-like uniform was firing shots with a handgun," he said. He says that the young people he talked to were hiding and dared not speak on the phone anymore for fear of being discovered by the perpetrator. "Young people have to swim in panic, and it is far to the mainland from Utøya. Others are hiding. Those I spoke with did not want to talk more. They were terrified," he said to VG Nett.

Police have confirmed the shooting incident, reports Reuters.

The news agency also quotes senior police officer, Thor Langli, saying the explosion that hit government buildings "may have been a car bomb".

Anti-terrorism police are being sent to Utøya where the Labour party youth camp has come under fire, the BBC is reporting. NRK says five people have been injured.

Andrew Boyle, a journalist in Norway, has sent me the following:

There are 700 people on the island camp. At 5.20 pm ambulance personel were told not to proceed out to the island because there was still shooting there. One Labour youth member tweeted: "We are sitting down by the beach. A man is shotting clothed in a police uniform. Help us! When are the police coming to help us!" Police stormtroopers are about to land on Utøya island from helicopters. Shooting still going on. Eyewitness describes shooting from his position on the mainland: "There is a little war going on out there"

In central Oslo, the train station has been evacuated as well as the headquarters of broadcaster TV2 because of suspicious packages.

John Magnus, chief foreign correspondent of Oslo's VG newspaper, told the Guardian he was sitting at his desk when the massive explosion in central Oslo today blew him off his chair.

It was 3.26 in the afternoon. The whole building was shaking. It was dancing. There was glass flying through the newsroom. I was on the far side of the building from where the prime minister's office is. The entire glass front of our building has been blown out ...



I saw people screaming and covered in blood. There were at least four people I saw who looked lifeless with their faces covered. We've had it confirmed that two people are dead but there are other locations that the emergency services have not reached yet.

Alyssa Nilsen told the Guardian: "My entire building was shaking ....People are lying across the street everywhere, I've seen people hanging out of the windows."



The Guardian has a gallery of today's tragic events.



View Oslo attack, July 2011 in a larger map

Here's a map of the areas targeted by attacks today, provided by my colleague Paddy Allen:

NRK is reporting that an unknown group called "Helpers of the Global Jihad" have posted a message that this is only the beginning of the reaction to Norwegian periodicals publishing the Muhammed cartoons, according to Andrew Boyle, a journalist in Norway.

Update: This website has some more details, although the group is said to be called Ansar al-Jihad al-Alam.

NRK is reporting that one person has been arrested on the island of Utøya, where the shooting took place.

Four people have been killed on the island of Utøya, an official from the AUF, the youth wing of the Labour party, told Varden (Update: TV2 is now reporting "several" people shot dead):

County Secretary Telemark AUF says that there is panic on the summer camp of the Labour Party's Youth Camp. There has been a shootout. Are there any that are damaged? Many people are shot. Have you seen any dead? Based on what I have seen, at least four people are shot and killed. Now it's complete panic and we swim off to get to safety.

This post has been removed because the video appears to be fake (thanks to all who pointed this out).

Police are saying they believe the person(s) responsible for the bomb to be foreign, according to the BBC.

But the attacker in Utøya, now arrested, looked Norwegian, NRK reports (thanks to @Pb1231 for the link)

Witnesses who have managed to escape from the island, says to NRK reporters on the spot that the perpetrator had a Norwegian look. He should be between 185 to 190 cm tall and have blond hair.

Norwegian media is now reporting seven people killed by the bomb blast and two seriously injured.

The New York Times has more on the claim of responsibility by an Islamist group (thanks to Marta Hernandez Salvan for passing this on):

A terror group, Ansar al-Jihad al-Alami (the Helpers of the Global Jihad), issued a statement claiming responsibility for the attack, according to Will McCants, a terrorism analyst at CNA, a research institute that studies terrorism. The message said the attack was a response to Norwegian forces' presence in Afghanistan and to unspecified insults to the Prophet Muhammad. "We have warned since the Stockholm raid of more operations," the group said, apparently referred to a bombing in Sweden in December 2010, according to Mr McCants' translation. "What you see is only the beginning, and there is more to come." The claim could not be confirmed.

This is Hannah Godfrey taking over from Haroon Siddique

An eyewitness has told Norway's NRK broadcaster he saw more than 20 bodies at camp shooting.

Former Guardian staffer Neil Perry, based in Oslo, is watching Norwegian television and tells me they are showing images taken from a helicopter showing people swimming in the water off Utøya Island, presumably they threw themselves into the sea to get away from the gunman. An eyewitness has reported bodies of people who had been shot floating in the water.

President Obama has said that the bomb blast in Oslo is a reminder that the world has a stake in stopping acts of terrorism. He expressed his condolences to the Norwegian people, and offered U.S. assistance with the investigation.

It's a reminder that the entire community has a stake in preventing this kind of terror from occurring

Obama said.

Oslo police have said they suspect the man arrested after the youth camp shooting is also linked to the bombing in Oslo.

Acting Police Chief Sveinung Sponheim won't give any details about the man, who was dressed in a police uniform when he opened fire.

He said police were still trying to get an overview of the shooting at the Utøya youth camp and could not say whether there was more than one shooter.

Here are the main points made in recent police press conference, according to an email sent to me by Henrik Hildre:



- 9 or 10 people confirmed dead at Utøya so far, preliminary search completed, they are now conducting a more thorough search.

- Several injured, no definite number.

- No more dead found in Oslo.

- The arrested man is talking to the police. He was arrested wearing a blue top with a police logo.

According to David Berry, from the department of Political Studies at Swansea University, on NRK in the last few minutes they interviewed the head of police in Oslo and he stated that the gunman was NOT wearing a police uniform, rather a blue jumper which had a Norwegian police badge or sign on it. He also confirmed that the suspect had never worked for the police.

On Twitter runehak, who works for the Norwegian Broadcasting Corporation, says:

News agency NTB says police do NOT think this is international terrorism. #osloexpl #oslobomb #whys

and then

Nationen also writes police think its a local variant directed at the current political system. http://j.mp/o6QQSP #osloexpl #oslobomb #whys

David Cameron David Cameron has pledged Britain's help to track down what he called the "evil" perpetrators behind the Norway attacks.

Diplomats are currently seeking to establish whether any UK nationals had been caught up in the carnage.

The Norwegian justice minister has confirmed at a news conference that the suspect arrested today at the youth camp in Utøya was Norwegian.

Neil Perry tells me the police have said that the same man was seen at the site of both attacks.

He thinks this is starting to look less like the work of international terrorists and more like that of a lone attacker with a grudge against the government.

Police have linked the suspect they are holding to both attacks.

Norway's Prime Minister Jens Stoltenberg has confirmed that the current number of people killed at the youth camp was nine or 10, but said police, "fear that there could be more."

On BBC's Newsnight Security Correspondent Gordon Corera says a youth rally is not a usual type of target for an Islamist terrorist - a factor which suggests the attacks may have been carried out by someone with a national agenda, but he points out that the car bombing in Oslo was big, so it would have been a lot for someone working alone to achieve.

AP has this:

A Norwegian police official says the 32-year-old Norwegian man suspected of the Oslo bombing and a shooting at a youth camp does not appear to be linked to Islamist terrorism.

The official says the attacks probably have more in common with the 1995 attack on a U.S. federal building in Oklahoma City than the Sept. 11, 2001 attacks.

He says the suspect appears to have acted alone, and "it seems like that this is not linked to any international terrorist organizations at all." He added that the investigation is still ongoing and that things can change.

The official was speaking on condition of anonymity because that information has not yet been released by Norway's police.

ketilbstensrud, who has worked for the Independent and the Daily Mirror, and now works for Radio NRJ Kristiansand, has tweeted this:

Just been directed to what is reportedly the Facebook profile of the Utøya gunman. For obvious reasons I cannot share that yet. Looks crazy. The gunman had his own company, dealing with geofarming, which would explain access to explosives. The Oklahoma bomb was made of ammonium nitrate, which is frequently used in geo-farming. The Utøya gunman has a company dealing with it... The 32 year old ethnic Norwegian national arrested for the Utøya shootings belongs to a right-wing group, reports TV2.



These images, from the Dagbladet site (directed to me by Neil Perry), were filmed a few moments after the Oslo blast, and give a sense of the power of the blast.

Police have confirmed 17 deaths in the Oslo bombing and youth camp shooting spree but expect the number to rise, according to AP.

National police chief Sveinung Sponheim says seven people were killed by the blast in Oslo, four of whom have been identified, and that nine or 10 people were seriously injured.

A homegrown terrorist set off an explosion that ripped open government buildings in central Oslo on Friday, he then went to a summer camp dressed as a police officer and gunned down youths as they ran and even swam for their lives, according to police.

These are the worst attacks this peaceful nation has seen since the second world war.

I am wrapping up this blog now, I'm sure we will have more news on this story in the morning.