Anders Behring Breivik, the Norwegian terror suspect in twin attacks last week that killed at least 76 people, was likely insane and was on drugs at the time, says his lawyer.
Geir Lippestad, a public defender, said that the 32-year-old Christian "crusader" believed he was in a war, Los Angeles Times reports.
Breivik, who is being held in solitary confinement over the attacks which have left Norway in shock and mourning, also expressed surprise that Norwegian police took so long to stop his attack, Lippestad said.
He thought that after he bombed a government building in Oslo, killing eight people, that he would be caught before reaching the island retreat of Utoya where another 68 youths at a Labor Party camp were massacred, The New York Times reports.
The attacks last Friday were the worst massacres in postwar Europe.
"This whole case has indicated that he's insane," Lippestad told reporters in Oslo.
Lippestad confirmed that Brievik told police about two other alleged terrorist cells operating in Norway and others outside the country, but that he provided no other details.
He said Breivik believes he is leading an anti-Muslim revolution to overturn Western governments and that the victims from his Oslo bombing and Utoya Island shooting rampage were casualties of war, LA Times reports.
(More in-depth coverage from GlobalPost.com: Norway names victims of attacks by Anders Breivik, and Is Breivik part of a movement?)
"He says he is sorry that he had to do this, but it was necessary to start a revolution in the Western world," Lippestad said. "He believes he is in a war."
It is likely that Breivik will plead insanity. He has already confessed to the attacks, authorities say.
However, given the planning involved in both attacks some legal experts have raised questions about how that would be possible.
Also, in his 1500-page manifesto, Brievik said he felt such violence was necessary to achieve his revolution and predicted that he would be declared insane.
University of Oslo law professor Stale Eskeland said an insanity plea was his best option in any trial - if he is declared fit to stand trial.
"I don't think there are any other possibilities for this defendant," he said.