The human rights of Norwegian right-wing extremist Anders Behring Breivik have been violated in prison, a court has ruled.
Breivik was convicted of terrorism and mass murder and jailed for 21 years in 2012.
The year previously he had killed 77 people in attacks on two parts of Norway.
But the Oslo district court ruled on Wednesday that his prison conditions breached an article in the European Convention on Human Rights prohibiting inhuman and degrading treatment, the Associated Press reported.
The ruling specifically cited Breivik's isolation in two different prisons since his arrest on July 22, 2011.
It also said authorities hadn't given enough attention to his mental health when determining his conditions in prison.
The court dismissed Breivik's claim that the government had also violated his right to respect for private and family life. It ordered the government to pay Breivik's legal costs of 331,000 kroner - about $41,000.
"The prohibition of inhuman and degrading treatment represents a fundamental value in a democratic society," the court said. "This applies no matter what - also in the treatment of terrorists and killers."
Breivik sued the government, saying his isolation from other prisoners, frequent strip searches and the fact that he was often handcuffed while moving between the three cells at his disposal violated his human rights.
During a four-day hearing at the Skien prison where he is serving his sentence, he also complained about the quality of the prison food and about having to eat with plastic utensils.
The government rejected his complaints, saying he was treated humanely despite the severity of his crimes.
In 2014 police rejected a lengthy complaint from Breivik, who claimed his treatment in jail – including the quality of his video games – amounted to “serious torture.”
In a four-page hand-written letter to penitentiary officials, Breivik described the prison where is being held as “hell” and made a list of 12 demands to improve the “torture-like” conditions he claimed he is being forced to live in.
Breivik's requests included that the Playstation 2 he has access to is replaced by a more recent Playstation 3. He also requested a computer to replace his “worthless” typewriter.
He also requested a sofa to replace the “painful” chair in his cell and that his weekly allowance be doubled to £60.
"You've put me in hell ... and I won't manage to survive that long. You are killing me," he wrote.
Breivik's attacks shocked on Norway on July 22, 2011. After months of meticulous preparations, he set off a car bomb outside the government headquarters in Oslo, killing eight people and wounding dozens.
He then drove to Utoya island, where he opened fire on the annual summer camp of the left-wing Labor Party's youth wing. Sixty-nine people were killed, most of them teenagers, before Breivik surrendered to police.