(CNN) -- A Norwegian court concluded Monday that Anders Behring Breivik -- the man charged with killing 77 people last July, an attack he claimed merited a medal of honor -- can legally be kept in custody until his trial starts in April, according to court documents.
The court acknowledged that Breivik's mental health remains an issue, noting that he may not be able to get the maximum possible punishment for the crimes if he's deemed insane.
Even so, the court found legal basis to keep him in custody for the next two months because prosecutors have said that if Breivik is found insane, they will push for him to be confined to a mental health facility, court documents state.
Breivik is accused of killing eight people in a bomb attack in Oslo and 69 more in a gun rampage on nearby Utoya Island on July 22. It was the deadliest attack on Norwegian soil since World War II. The latter victims were among 700 mostly young people attending a Labour Party camp on the island.
He has pleaded not guilty, though he has admitted carrying out the attacks, the judge handling his case said previously.
In November, prosecutors said psychiatrists had determined Breivik was paranoid and schizophrenic at the time of the attacks and during 13 interviews experts conducted with him afterward.
Judge Wenche Elizabeth Arntzen told reporters in January that the court requested a second opinion because of the importance of the question of his sanity to Breivik's trial.
Two new psychiatrists were subsequently assigned to carry out the evaluation, court spokesman Geir Engebretsen said.
Breivik reiterated some of his extremist views during Monday's court hearing, which began with him entering with a smile and offering up a raised, clenched-fist salute in solidarity.
Confirming accounts posed to him by Norwegian reporters, his lawyer, Geir Lippestad, said Breivik said he did not accept the legitimacy of the presiding judge because he didn't believe in the multicultural Norway that the judicial system is part of. The lawyer's back-and-forth with reporters was captured by Norwegian media, including national broadcaster NRK.
Breivik further claimed the shooting rampage was a matter of self-defense, meant to save Norway from being taken over by multicultural forces and prevent ethnic cleansing of Norwegians, according to Lippestad.
Rather than punishment, Breivik said he deserved a medal of honor, a statement that prompted derisive laughs from victims and relatives of those killed on Utoya Island.
He also said nobody could believe that he was insane, describing questions about his mental makeup as ridiculous, Lippestad confirmed.
Scheduled to begin April 16, Breivik's trial is expected to last 10 weeks.
Authorities have described him as a right-wing Christian extremist. A 1,500-page manifesto attributed to Breivik posted on the Internet is critical of Muslim immigration and European liberalism, including Norway's Labour Party.
The manifesto predicts that a "European civil war" will lead to the execution of "cultural Marxists" and the banishment of Muslims.
Prime Minister Jens Stoltenberg said in the aftermath of the attacks that his country had been fundamentally changed, but vowed that Norway would remain "an open society."
Journalist Olav Mellingsaeter in Oslo contributed to this report.