Anders Behring Breivik, who is facing trial for the slaughter of 77 people, told a court on the second day of his hearing that he "would do it all again".
Breivik, who killed eight people in a bomb attack in Oslo before travelling 25 miles to Utoya island to shoot 69 more, was allowed to read a 30-minute statement to the court.
In the statement, which was not broadcast to avoid giving Breivik a pulpit from which to espouse his far-right ideals, the killer claimed he has carried out "the most sophisticated and spectacular political attack committed in Europe since the Second World War".
In a rambling address that repeatedly saw judge Wenche Elizabeth Arntzen ask him to cut to the point, Breivik said he had lowered his rehtoric "out of consideration for the victims".
He said he carried out the violent attacks for good, to avoid the outbreak of a war over multiculturalism. He said the people of Norway had become "second-rate citizens" who will lose their culture and way of life.
He blamed the left-wing bias of the Norwegian media for his portrayal as a monster, arguing that the public did not see the "real" him.
"I am not scared of the prospect of being imprisoned. I was born in a prison and I spent my life in a prison. This prison is called Norway," he said.
His diatribe touched upon "cultural Marxists", Adolf Hitler, the McCarthy witch-hunts and an article on multiculturalim printed in the Times in 2010.
Breivik, 33, repeatedly argued with the prosecution lawyers and judge, who asked for him to moderate his language and finish the talk, which stretched beyond half an hour. He argued that his statement was the basis for his entire defence.
Trgyve Sorvaag, a freelance reporter inside the court, tweeted: "People clearly want Breivik to finish his speech. People express despair when Breivik says he still has one page left."
The killer, a former telephone salesman with a history of failed business ventures, admits carrying out the killings, but denies legal culpability for the crimes.
He claims that he carried out the attack out of "necessity" as a form of self-defence under section 47 of the Norwegian penal code.
A panel of five judges must make a majority decision on Breivik's mental state and legal culpability. Two assessments of his mental state have been made since the attacks, one concluding that he was insane, the other sane.
The start of the second day of the trial was delayed when it was revealed that one of the lay judges, Thomasn Indrebo, had posted on Facebook prior to the case that the only just punishment for Breivik was the death penalty. He was dismissed from the case.
The trial's first day saw Breivik refuse to acknowledge the authority of the court, which he believes "gets its politcial mandate from forces that support multiculturalism".
He became tearful when a short video of his own Knights Templar Manifesto was played to the court.
The trial, expected to last until June 20, continues.