Anders Behring Breivik was declared insane and may face compulsory treatment for killing 77 people in his July 22 twin attacks on Oslo government offices and a Labor Party youth camp south of the Norwegian capital.

Breivik suffers from paranoid schizophrenia and is ‘‘delusional’’ according to a court ordered evaluation, prosecutor Svein Holden said today at a press conference in Oslo, after being presented with a 243-page report by forensic psychiatrists Torgeir Husby and Synne Soerheim.

The report was based on 13 talks with Breivik over a 36-hour period.

The evaluation, which will need approval by the Board of Forensic Medicine, may mean that the 32-year-old will be placed in compulsory psychiatric treatment, potentially for as long as life, rather than prison.