Oslo District Court ruled his rights were violated by keeping him in isolation
Mass killer Anders Breivik has given a Nazi salute at a court case into a ruling that his human rights were violated in prison.
The 37-year-old far-right extremist made the gesture as he entered the court in a converted gym at the high security Skien Prison, where he is incarcerated.
Norway is trying overturn a surprise ruling by Oslo District Court that it violated his human rights by keeping him in isolation since he carried out a bomb and shooting massacre of 77 people in 2011.
In March last year, a judge agreed that Oslo had violated a ban on "inhuman and degrading" treatment under the European Convention of Human Rights.
Breivik has sued the Norwegian government, claiming solitary confinement, frequent strip searches and the fact he was often handcuffed during the early part of his incarceration had violated his rights.
The ruling said "the prohibition of inhuman and degrading treatment represents a fundamental value in a democratic society. This applies no matter what - also in the treatment of terrorists and killers".
It also ordered the government to pay Breivik's legal costs of 331,000 kroner (€36,481).
But it dismissed his claim that his right to respect for private and family life was violated by restrictions on contacts with other right-wing extremists.
Breivik was convicted of mass murder and terrorism in 2012 and given a 21-year prison sentence that can be extended if he is deemed a danger to society.
He is being held in isolated in a three-cell complex where he can play video games, watch TV and exercise.
He also complained about the quality of prison food, having to use plastic utensils to eat and not being able to communicate with sympathisers.
But Norway's government has said he is treated humanely and that he must be separated from other inmates for safety reasons.
On July 22nd 2011, he set off a car bomb outside the government headquarters in Oslo, killing eight people.
Dressed in a police uniform, he then drove to the island of Utoya where he killed 69 others - mainly teenagers - at the annual summer camp of the left-wing Labor Party's youth wing.
The hearing is expected to last six days.