Jailed Norwegian mass murderer Anders Behring Breivik has given a Nazi salute upon returning to court to argue that his isolation violates his rights.
The right-wing extremist says he is being held in inhuman conditions but the state rejects this.
Breivik killed 77 people in 2011 when he bombed central Oslo before going on a shooting spree at a Labour Youth camp on the island of Utoya.
He was sentenced to 21 years in prison in 2012.
Tuesday's hearing, in a prison gym converted into a court, marks his first public appearance since then.
He entered the court in a grey suit shortly before 09:00 (08:00 GMT). He shook hands with his lawyers and made the Nazi salute after police removed his handcuffs.
Breivik, 37, is mainly challenging the government over his solitary confinement, as well as over general conditions including what he claims is the excessive use of handcuffs.
In his opening statement, Breivik's lawyer Oystein Storrvik said his client's punishment was worse than the death penalty, which is outlawed in Norway.
Breivik accuses the Norwegian government of breaching two clauses of the European Convention on Human Rights (ECHR).
One of the clauses guarantees the right to respect for "private and family life" and "correspondence", while the other prohibits "inhuman or degrading treatment or punishment".