Oslo, Norway (CNN) Norwegian mass murderer Anders Behring Breivik has won part of his lawsuit against the state over his solitary confinement in a high-security prison, a court announced Wednesday. The Oslo district court found the 37-year-old's treatment in prison violated Article 3 of the European Convention on Human Rights, prohibiting "inhuman or degrading treatment," and ruled that his conditions must be eased. The court also ordered the government to pay legal costs of 331,000 kroner ($40,600) for the right-wing extremist, who killed 77 people in a shooting rampage and bombing attack in 2011. Report: Sandy Hook shooter tried to emulate Norway massacreMass killer wins part of lawsuit against Norwegian state for breaching his rightsCourt rules his treatment was in breach of rules prohibiting "inhuman or degrading treatment"Right-wing extremist killed 77 people in 2011 in Norway's deadliest attack since World War II
Appearing in public for the first time since his trial, Breivik gave testimony during the suit, alleging that his isolation in prison constituted a "sadistic" attempt by _ authorities to kill him.