SKIEN PRISON: Mass murderer Anders Behring Breivik made a Nazi salute on Tuesday as his lawsuit opened against Norway over his prison conditions, confirming fears he would use it to grandstand his extremist views.

Despite the theatrical entrance, Breivik’s lawyer Oystein Storrvik insisted the suit, which contends his prison isolation constitutes “inhuman” treatment, was necessary because his client would likely be spending the rest of his life behind bars.

“This case is about something much more than what many people think, just a lawsuit brought to allow Breivik back into the spotlight to explain himself,” Storrvik said.

“This case is simply about his detention conditions for the rest of his life,” he said in the makeshift courtroom set up in the gymnasium of the Skien prison where the killer is being held and where a climbing wall, two basketball hoops and exercise bars were visible.

Breivik is serving a maximum 21-year sentence for killing eight people in a bomb attack outside a government building in Oslo in July 2011, then murdering another 69 people, most of them teenagers, in a rampage at a Labour Youth camp on the island of Utoya.

His prison sentence can be extended if he is still considered a danger to society.

Sporting a shaved head and a dark suit with a white shirt, Breivik entered the courtroom, turned toward the media present and extended his right arm.

On several occasions during his 2012 trial, he made a variation of the Nazi salute by holding his closed right fist to his heart and then extending his arm.

“Incredibly provocative,” reacted Berit Reiss-Andersen, one of the lawyers for the victims’ families in his 2012 trial, speaking on television channel TV2.

The Nazi salute appears to confirm the belief that he has radicalized in prison, having recently described himself as a “militant nationalist.”

In a letter to AFP dated Oct. 27, 2014, he said he had pledged his “allegiance to national socialism.”

Breivik has in the past likened his prison conditions to “torture.”