Experts told a Norwegian court on Wednesday that the mass murderer Anders Behring Breivik does not suffer from a mental illness, in a trial to determine whether the convicted far-right terrorist could be released early on parole.

Anders Behring Breivik, the jailed mass murderer who killed 77 in Norway's worst peacetime atrocity, told a court his attacks were "necessary" as he asked for early release on Tuesday, but a prosecutor said he remained dangerous and should not be freed.

Norwegian far-right extremist Anders Behring Breivik, who killed 77 people in a bombing and shooting rampage in 2011, has made another application for parole after spending more than a decade behind bars.