• 1.30pm: Massive car bomb explosion kills at least seven in Oslo
• 3.30pm: Between 25 and 30 dead as man disguised as police officer opens fire on island youth meeting Norwegian prime minister was due to attend
• Eyewitnesses say bodies floating in the sea around the island
• Man arrested on the island was 6ft tall, had blonde hair and spoke Norwegian–reports he was shot and wounded before being detained
• Police fear explosives may have been laid at camp
• Unknown group called ‘Helpers of the Global Jihad’ said to have posted message saying this is reaction to publication of Muhammed cartoons
• Islands residents told not to reveal their location on Twitter or Facebook
• British Foreign Minister William Hague condemns ‘horrific’ attack
• Oslo Mayor: ‘Wish I were on island to be shot instead of children’
• Police believe the two attacks may be linked and can not say whether there was more than one shooter on island
Teenagers on the Norwegian holiday island of Utoya had to ‘swim for their lives’ and hide in trees when a gunman fired indiscriminately at them.
Around 700 had gathered on the island for a meeting of the youth wing of the ruling Labour party.
Witnesses said the man in police uniform who opened fire beckoned several young people over before shooting at them. He told them to ‘come here’.
Other witnesses said they heard him saying: ‘This is just the beginning.’
It came as Norway succumbed to a double attack in what is being described as the worst atrocity it has faced since the Second World War.
Terrorists are believed to be responsible for a massive car blast at a government office block in the capital Oslo which took place earlier on in the day.
One teenager who was caught up in the island attack said: ‘Suddenly, we heard lots of shooting. People had to run and hide. We have been told to get off the island.’
A party official said: ‘There has been a shootout. Many people are shot. 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.’
Bjorn Jarle Røberg-Larsen, of the Labour party, spoke to young people on Utoya by phone.
‘They say that at least one person wearing a police-like uniform was firing shots with a handgun,’ he said.
He said the people he spoke to were hiding and dared not speak on the phone any more for fear of being discovered.
‘Young people have to swim in panic, and it is far to the mainland from Utoya,’ he said. ‘Others are hiding. Those I spoke with were terrified.’
A Twitter user going by the name zhalli1 posted a message on the website saying: ‘I’m safe. We’ve hidden in a tree. One of us is shot twice in the foot.’
Police stormtroopers landed on the island by helicopter as the shooting continued and sealed off the area but ambulances were unable to reach the scene immediately.
Fredrik Walløe, a London-based Norwegian journalist, tweeted: ‘A Sea King helicopter carrying medics has reached the island, but can’t land because of continued gunfire.’
Locals were urged to help those fleeing the island.
Alyssa Nilsen, a music journalist and photographer in Oslo, wrote on Twitter: ‘People are escaping the island by jumping in the water and swimming away. Anyone near Utoya with a boat, please help!’
One witness described the scene from the mainland. He wrote on Twitter: ‘There is a little war going on out there.’
Prime Minister Jens Stoltenberg, who had been due to visit the island, told a Norwegian TV channel that the situation was critical.
He said: ‘We now have reports of a serious situation there–a critical situation on Utoya.’
Emilie Bersaas, 19, spoke from Utoya last night, from where she could still hear police and helicopters overheard.
She said: ‘I’m at a building with the army. I ran here when I heard the shooting. I heard a lot of people running and screaming. I ran to the nearest building and hid under the desk.’
She said there was ‘a lot of shooting’ and she heard ‘screaming from the next room’.
‘The shooting came from all different directions,’ she added. ‘Somebody told me to go under the desk. And put mattresses and pillows on top so I felt kind of safe. It was terrifying.’
She said the shooting was very close to the building and hit it at one point.
‘I stayed under the bed for two hours. Then the police smashed the window and came in.’
‘It seems so unreal, in Norway this doesn’t happen here. It’s something that we hear about happening in the U.S.
‘It’s weird and it’s tough and it reminds us of problems that we should have taken more seriously than we have.’
She added: ‘I’m worried about my friends on the island. I’ve talked to some of them. Some of them are hiding in the same building as me but some of them I don’t know where they are.’
The island attack came soon after a massive car blast at a government office block in the capital Oslo, where reports say a man also dressed in police uniform was seen loitering beforehand.
It has not been confirmed if the two incidents were coordinated or the island gunman was acting alone–but Oslo police believe the two incidents may indeed be linked.
They said they were still trying to get an overview of the Utoya massacre and could not say whether there was more than one shooter.
More than 30 are believed to have been killed–seven in Oslo and between 25 to 30 on Utoya Island, 50 miles north of the capital–where the prime minister Jens Stoltenberg had been due to attend the youth Labour Party event.
The man arrested is reported to be 6ft tall, blonde and spoke Norwegian.
Simen Braende Mortensen, a guard on the boat to Utoya Island, told VG newspaper he saw a man, aged between 30 to 40-years-old, in a police uniform and bulletproof vest drive on to the boat in a silver van.
He apparently had a pistol and a rifle with telescopic sight, had a Norwegian look and spoke in a common eastern dialect.
It is reported he said he had been sent to beef up security following the Oslo bombing, and was shot and wounded before being arrested.
Some people fled the attack by swimming away from the island and others locked themselves in buildings but reports emerged that explosives may have been set around the area.
They were warned not to reveal their location on social media networks, such as Twitter and Facebook, for fear they could be the victims of future attempts.
Victims of the first blast in Oslo were still being treated as news of the second incident filtered through.
Mr Stoltenberg, who was advised by security officials not to reveal his location, told journalists: ‘There is a critical situation at Utoya and several ongoing ops as we speak.
‘Co-workers have lost their lives today . . . it’s frightening. That’s not how we want things in our country.
‘But it’s important that we don’t let ourselves be scared. Because the purpose of that kind of violence is to create fear.’
Also police were this afternoon were investigating reports of a suspicious package at broadcaster TV2 in the capital.
At least 15 people were injured in the initial attack in Oslo. It is known that seven were being treated at Oslo University Hospital.
The tangled wreckage of a car was seen outside one Government building with officers investigating whether it was responsible for the blast and carrying a fertiliser nitrate device.
The attack occurred opposite the offices of the Norwegian prime minister whose windows were blown out by the force of the explosion.
Dozens of victims lay injured amid the wreckage and many were carried away from the scene bleeding.
All roads into the city centre have been closed, and security officials evacuated people from the area, fearing another blast.
Fortunately, it was a public holiday and the offices were less busy than during a normal weekday.
‘It exploded–it must have been a bomb. People ran in panic and ran. I counted at least 10 injured people,’ said Kjersti Vedun, who was leaving the area.
An NRK journalist, Ingunn Andersen, said the headquarters of tabloid newspaper VG had also been damaged.
‘I see that some windows of the VG building and the government headquarters have been broken. Some people covered with blood are lying in the street,’ she said.
‘It’s complete chaos here. The windows are blown out in all the buildings close by.’
Eyewitness Craig Barnes was behind the Government building that was struck.
He told Sky News: ‘I’m still shocked, I can’t believe it. I’ve got no words, I’m shaken up. Quite a few people are injured. It has shocked everyone and its a major holiday here. Everyone leaves here for two weeks from today.’
The Mayor of Oslo, Fabian Stang, said he did not believe Norway could have been attacked and initially hoped the explosion in the city had been caused by an accident.
He told Sky News he ‘wished he could have been there’ so that he could have stood ‘in front of the young people and ask the gunman to shoot me instead.’
Foreign Secretary William Hague said the UK stood ‘shoulder to shoulder’ with Norway.
The statement of support came as diplomats sought to check whether any British nationals were caught up in the carnage.
Mr Hague said: ‘I send my deepest condolences to all those who have lost relatives or been injured in today’s horrific bomb blast in Oslo.
‘Our Embassy stands ready to provide assistance to any British nationals who may have been caught up in the attack.
‘We condemn all acts of terrorism. The UK stands shoulder to shoulder with Norway and all our international allies in the face of such atrocities.
‘We are committed to work tirelessly with them to combat the threat from terrorism in all its forms.’
U.S. President Barack Obama said the incidents were ‘a reminder that the entire international community has a stake in preventing this kind of terror from occurring.’
Heide Bronke, a U.S. State Department spokeswoman, said Washington was monitoring the situation but did not have any word of U.S. casualties.
The attack came just over a year after three men were arrested on suspicion of having links to Al Qaeda and planning to attack targets in Norway.
Violence or the threat of it has already come to the other Nordic states: a botched bomb attack took place in the Swedish capital Stockholm last December and the bomber was killed.
Denmark has received repeated threats after a newspaper published cartoons of the Prophet Mohammad in late 2005, angering Muslims worldwide.
The failed December attack in Stockholm was by a Muslim man who grew up in Sweden but said he had been angered by Sweden’s involvement in the NATO-led force in Afghanistan and the Prophet Mohammad cartoons.
That attack was followed weeks later by the arrest in Denmark of five men for allegedly planning to attack the newspaper which first ran the Mohammad cartoons.
In July 2010, Norwegian police arrested three men for an alleged plot to organise at least one attack on Norwegian targets and said they were linked to individuals investigated in the United States and Britain.
John Drake, senior risk consultant at London-based consultancy AKE, said: ‘It may not be too dissimilar to the terrorist attack in Stockholm in December which saw a car bomb and secondary explosion shortly after in the downtown area.
‘That attack was later claimed as a reprisal for Sweden’s contribution to the efforts in Afghanistan.’
NATO member Norway has sometimes in the past been threatened by leaders of al Qaeda for its involvement in Afghanistan.
It has also taken part in the NATO bombing of Libya, whose leader Muammar Gaddafi has threatened to strike back in Europe.
Political violence is virtually unknown in a country known for awarding the Nobel Peace Prize and mediating in conflicts, including in the Middle East and Sri Lanka.
David Lea, Western Europe analyst at Control Risks, said: ‘There certainly aren’t any domestic Norwegian terrorist groups although there have been some Al Qaeda-linked arrests from time to time. They are in Afghanistan and were involved in Libya, but it’s far too soon to draw any conclusions.’