Police have charged a 32-year-old Norwegian man over both attacks.

The man dressed as a police officer was arrested on tiny Utoeya island after an hour-long shooting spree. The search for other possible victims continues.

The Oslo bombing killed at least seven. Prime Minister Jens Stoltenberg said the attacks were "like a nightmare".

Mr Stoltenberg, whose offices were among those badly hit by the blast, described the attacks as a national tragedy.

"Never since the Second World War has our country been hit by a crime on this scale," he told a news conference in Oslo.

He added that he was due to have been on Utoeya - "a youth paradise turned into a hell" - a few hours after the attack took place. Many others were injured there as well as those who died.