Anders Behring Breivik has vowed to go on hunger strike if he is not provided with up-to-date video games to better his stay at the Norwegian prison where he is jailed for killing 77 people.
In a hand-addressed letter to AFP news agency, Breivik claimed he faces living conditions akin to "torture" at the high security detention centre in Skien in south-eastern Norway.
The typed letter includes a list of 13 demands the mass murderer sent to Norwegian prison authorities in November.
Among the requests is that his PlayStation 2 games console be replaced with a Playstation 3.
Breivik, who turned 35 yesterday, also demanded he be allowed to choose "more adult games" to play.
Other requests included better conditions for his daily walk, access to a PC, the possibility to communicate more freely with the outside world, and the doubling of his weekly benefits, which currently amount to 300 kroner (£30).
"The hunger strike won't end until the Minister of Justice (Anders) Anundsen and the head of the KDI (the Norwegian Correctional Services) stop treating me worse than an animal," Breivik wrote.
The right-wing extremist killed 77 people in Norway on 22 July, 2011, in one of the worst terrorist attacks in Europe since the Second World War.
Eight people were killed in a car bombing in front of a government building in the centre of Oslo.
Later that day, Breivik shot another 69 dead on the Island of Utoya, where a youth camp run by the Labour party was being held.
In August 2012 he was sentenced to 21 years in jail by Oslo district court, after the five judges unanimously concluded that he was sane when he carried out the attacks.