Breivik raises his arm in a Nazi salute at the court room in Skien prison, March 15

OSLO — Norway violated terrorist Anders Behring Breivik’s human rights by keeping him in a “completely locked world” after being sentenced for killing 77 people in twin attacks in 2011, a court ruled on Wednesday.

The ruling, which took many by surprise, found that the killer had been subjected to strip searches, had been woken up hourly by guards for long periods and that the authorities had done little to alleviate the impact of his isolation.

A survivor of Breivik’s shooting spree said the decision “feels a bit like being punched in the gut” and a newspaper editorial denounced the decision as “wrong”. A law professor said it was likely to be appealed.

Breivik killed eight people in a bomb attack in Oslo in July 2011 before attacking a youth meeting of the Labor Party on an island to the northwest of the capital, killing 69 people.

He took Norwegian authorities to court in March, accusing them of exposing him to inhuman, degrading treatment or punishment in breach of the European Convention on Human Rights.

Breivik protested his isolation from other inmates and from outsiders who are not professionals.

His isolation is “an inhuman treatment” in the meaning of the European convention, the court said, noting that all his visits, except for his mother who died in 2013, are from professionals, and only through a glass wall.

The state must pay Breivik’s legal fees of $40,732.45, the judge ruled.

Ahead of the verdict, lawyers for both parties said they would appeal if it did no go in their favor.