gunman dressed in police uniform shot dead at least 85 people at a youth summer camp of Norway's ruling political party, hours after a bomb killed seven in the government district in the capital Oslo.
Witnesses said that the gunman, identified by police as a 32-year-old Norwegian who they believed was also linked to the bombing, moved across the small, wooded Utoeya holiday island on Friday firing at random as young people scattered in fear.
Norwegian television TV2 said the gunman detained by police was tall and blond and had links to right-wing extremism. Police said on Saturday that the man had been charged for the bomb blast and the shooting.
"A paradise island has been transformed into a hell," Prime Minister Jens Stoltenberg told a news conference on Saturday.
He said that he did not want to speculate on the motives of the attacks, but added: "Compared to other countries, I wouldn't say we have a big problem with right-wing extremists in Norway. But, we have had some groups, we have followed them before, and our police is aware that there are some right-wing groups."
Teenagers at the lakeside camp fled screaming in panic, many leaping into the water to save themselves, when the attacker began spraying them with gunfire, witnesses said. "I just saw people jumping into the water, about 50 people swimming towards the shore. People were crying, shaking, they were terrified," said Anita Lien, 42, who lives by Tyrifjord lake, a few hundred meters (yards) from Utoeya.
"They were so young, between 14 and 19 years old." Survivor Jorgen Benone said: "It was total chaos...I think several lost their lives as they tried to get over to the mainland. "I saw people being shot. I tried to sit as quietly as possible. I was hiding behind some stones. I saw him once, just 20, 30 meters away from me. I thought 'I'm terrified for my life', I thought of all the people I love.
Right-wing militancy has generated sporadic attacks in other countries, including the United States. In 1995, 168 people were killed when Timothy McVeigh detonated a truck bomb at a federal building in Oklahoma City.
Nato member Norway has been the target of threats before over its involvement in conflicts in Afghanistan and Libya. 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. In Oslo, the building of a publisher which recently put out a translation of a Danish book on the cartoon controversy was also affected, but was apparently not the target.
The Oslo district attacked is the very heart of power in Norway. Nevertheless, security is not tight in a country unused to such violence and better known for awarding the Nobel Peace Prize and mediating in conflicts, including the Middle East and Sri Lanka.