Behring Breivik, 32, was detained for allegedly shooting at least 85 people dead at a youth Labour Party meeting on an island and killing seven more in a car bomb in central Oslo, damaging a government building.
"He admitted responsibility," lawyer Geir Lippestad told the Norwegian television station on Saturday.
"He explained that it was cruel but that he had to go through with these acts," Lippestad said, and that the attacks were "apparently planned over a long period of time".
Norway was in shock last night as it tried to come to terms with the horrific murder of at least 92 of its citizens – most of them young people - in a bomb and gun massacre.
Knut Olav Åmås is the culture and op-ed editor at Aftenposten, Norway's leading newspaper said the country lost its innocence this weekend.
“The events of this weekend have given many Norwegians a sense of alienation towards their country. We have lost that feeling of safe and secure normality that Norwegians are so predisposed to take for granted,” he wrote in the Guardian.
Norway's Prime Minister Jens Stoltenberg and the country's King Harald, Queen Sonja and Crown Prince Haakon converged on a hotel near where the shootings took place to comfort survivors and family members.
Stoltenberg promised that the country’s long history of pacifism would remain despite the violence.
''No one will bomb us to silence. No one will shoot us to silence. No one will ever scare us away from being Norway,'' he said in a public address yesterday.
''You will not destroy us. You will not destroy our democracy or our ideals for a better world.''
Norway prides itself on being one of the most politically harmonious countries in the world. It is home to the Nobel peace prize and the International Peace Research Institute.
''Attacking one of the most peaceful places, a political youth camp, is especially brutal - an act of cowardice,'' Stoltenberg said.
According to the Sydney Morning Herald, Stoltenberg had been due to give a speech yesterday at the island of Utoeya where the shootings took place. About 700 young people were attending the camp organized by the youth wing of his Labour Party.
US President, Barack Obama, said the attacks were ''a reminder that the entire international community has a stake in preventing this kind of terror from occurring''.
NATO's Secretary-General, Anders Fogh Rasmussen, condemned the ''heinous act''.
In Oslo, hundreds came to pay their respects at a makeshift shrine on the doorstep of Oslo's cathedral. The bomb site is just two streets away.
"It will take us a long time to get over this," said Hilde Stenseng, 30, a civil servant told a reporter from the Telegraph.
"There are soldiers on the streets and everyone is much more quiet. We are a small country, so everyone is affected. You can guarantee that somehow we will all know people, or know someone who does, that have been caught up in this. It's a national outpouring of grief."
Knut Olav Åmås wrote, “So many of us are afraid that the events of Friday could change Norway forever, characterized as it is by a high degree of openness and egalitarianism.
He fears the trust between Norwegians will be damaged irreparably after the massacre. “It is not unusual to meet cabinet ministers accidentally on the street, or our foremost celebrities in grocery stores. A sort of charming naivety has been our hallmark, combined with a considerable degree of homogeneity.”