"I did not execute [terrorist attacks] on July 22. Blood & Honour bears the major responsibility ... Internet radicalization is responsible for it," Breivik told the court, as quoted by Norwegian broadcaster NRK.
He said he regretted becoming "radical and militant."
In July 2011, Breivik detonated a bomb in Oslo, killing eight people, and shortly after carried out a mass shooting at a youth camp in Utoya, killing 69 more. He was sentenced to 21 years in prison. Soon after his arrest, Breivik confessed to committing the attacks but has yet to plead guilty.
Under Norwegian law, Breivik had the right to apply for parole after serving a decade in prison, and can reapply for a parole hearing every year thereafter. The Norwegian prosecutor's office is opposed to parole for Breivik, saying he still poses threat to society.
Blood & Honour is a neo-Nazi group founded in the United Kingdom in 1987 to promote white nationalism.