Norwegian police on Saturday described the main suspect in twin bomb and shooting attacks that left at least 91 dead as a Christian fundamentalist.

A police official said that information gleaned on the internet suggested the 32-year-old ethnic Norwegian was a "Christian fundamentalist."

The gunman who killed more than 80 people in Norway on Friday has been named as Anders Behring Breivik, but police refused to confirm his identity.

Police chief Sveinung Sponheim said his internet postings "suggest that he has some political traits directed toward the right, and anti-Muslim views".

"But whether that was a motivation for the actual act remains to be seen," he told Norwegian broadcaster NRK.

On the Facebook page attributed to him, he describes himself as a Christian and a conservative, according to the BBC.

Investigators believe he is behind both attacks but do not rule out more arrests, Andersen said.

Police questioned the blond 32-year-old suspect Saturday over twin attacks on a youth camp and the government headquarters that killed at least 91 people in Norway's deadliest tragedy since World War II.

As harrowing testimony emerged from the holiday island where scores of youngsters were mown down by a gunman dressed as a policeman, Norway's premier said the country would emerge stronger from the "cruel act of violence".

"Never since the Second World War has our country been hit by a crime on this scale," Jens Stoltenberg told journalists in an early morning press conference as police searched for more bodies on the idyllic Utoeya island.