SKIEN, Norway (AP) — Norwegian mass murderer Anders Behring Breivik told a panel of judges Thursday that his solitary confinement in prison had deeply damaged him and made him even more radical in his neo-Nazi beliefs.

Dressed in a black suit, the right-wing extremist who killed 77 people in a 2011 bomb attack and shooting spoke coherently and without emotion as he addressed the panel considering if his isolation is inhumane.

“I have been damaged by the isolation … (and) radicalization has been a consequence of it,” a stone-faced Breivik said. “I have not been a little hurt, I have been very damaged.”

Breivik, 37, was speaking during a hearing at the high-security prison in southern Norway where he is serving a 21-year sentence and has been in solitary confinement since 2012.

The government is appealing a lower court ruling that held his constant segregation was degrading and violated European human rights standards.

Saying he felt locked in a bubble, Breivik complained about his lack of personal contacts. He is allowed to receive visits from family and friends, but hasn’t had any except one from his mother before she died.

The self-proclaimed neo-Nazi also told the three-judge panel he agreed with government attorneys’ evaluation that he had become more radicalized in prison.

The government maintains that the convicted killer is dangerous and must remain kept away from other inmates at the high-security prison in Skien, where the appeals case is also being heard.

Attorney General Fredrik Sejersted, representing the government, said that before Breivik carried out the 2011 massacre, he had envisioned continuing to be a fascist, right-wing extremist leader if he ended up in prison instead of killed by police during the attacks.

Sejersted said Breivik lives in conditions that are better than the ones for many other inmates. In compensation for his solitary confinement, he has a three-cell complex where he plays video games, watches TV and exercises. Breivik also is served coffee and newspapers in the morning.

But he cautioned that he continues to spread extremist ideology through his writings, and that all his correspondence should still be monitored and his letters opened.

He told the court that Breivik continues to try to find ways of bypassing censorship of his correspondence, including an ad to find a marriage partner.

Breivik is still “very deeply engaged in his political right-wing, extremely neo-Nazi project,” Sejersted said.

In July 2011, Breivik killed eight people with a bomb at government headquarters and fatally shot another 69 on Utoya island, mainly teenagers at a left-wing political summer camp.

Breivik sued the government last year, arguing that his solitary confinement, frequent strip searches and frequent handcuffing during his early incarceration violated his human rights.

In a surprise decision, the Oslo District Court in April sided with his claim, finding that his isolation was inhuman, degrading and a breach of the European Convention on Human Rights. The court ordered the government to pay Breivik’s legal costs.

But it dismissed Breivik’s claim that his right to respect for private and family life was violated by restrictions on contacts with other right-wing extremists, a decision that Breivik in turn is appealing.

Defense lawyer Oystein Storrvik said the control over his communications with the outside world amounts to a “blatant breach of human rights.” Frequent censorship of his letters and long review periods means Breivik cannot keep regular communication with people outside of the penal system, Storrvik said.

Psychiatrist Randi Rosenqvist, who is responsible for evaluating his mental health in prison, said she is convinced Breivik is neither suicidal nor schizophrenic, but suffers from anti-social personality disorder.

Rosenqvist said Breivik receives some stimulation from the outside world through interactions with prison staff, doctors and a priest. She said she does not consider him isolated, even though the encounters take place through a glass wall.

At the time of the murders, Breivik claimed to be the commander of a secret Christian military order plotting an anti-Muslim revolution in Europe. He now describes himself as a traditional neo-Nazi who prays to the Viking god Odin.

Asked several times during Thursday’s hearing whether he would denounce the July 2011 attacks, Breivik said it was not possible because he considers it a historic event.

“The event is too great to choose another narrative,” he said, adding that he doesn’t advocate further violence.

Six days have been reserved for the hearings by the Borgarting Court of Appeals in the makeshift courtroom in the gym of the prison in Skien, 135 kilometers (85 miles) southwest of the capital, Oslo. They are scheduled to end Jan. 18, with a ruling expected in February.