Norway massacre: Breivik declared insane

They believe he was in a psychotic state both during and after the twin attacks on 22 July that led to the deaths of 77 people and injured 151.

Their report must still be reviewed by a panel of forensic psychiatrists.

Breivik will still be tried in April but it seems likely he will be placed in psychiatric care rather than prison.

Breivik admits carrying out the attacks but has pleaded not guilty to charges, arguing that that the attacks were atrocious but necessary for his campaign to defend Europe against a Muslim invasion.

The two psychiatrists who interviewed him on 13 occasions concluded that he lived in his "own delusional universe where all his thoughts and acts are guided by his delusions", prosecutors told reporters.

The 243-page report will be reviewed by a panel from the Norwegian Board of Forensic Medicine.

Breivik, 32, is due to stand trial on 16 April for a hearing scheduled to last around 10 weeks.