Anders Behring Breivik will be kept in prison for at least the next eight weeks while prosecutors investigate his claims that he did not act alone.
The judge says he will be kept in solitary confinement with no incoming letters, access to media or visitors except for his lawyer.
The judge granted prosecutors’ request for Breivik to be put on remand to give them more time to carry out further inquiries.
In court, he claimed there were two more groups of collaborators at work. He had previously claimed to have acted alone.
The trial could be up to a year away.
Meanwhile, the death toll from Friday’s bomb attack and shootings has been revised down by Norwegian police.
They now say 76 people are known to have been killed. The total had previously been put at 93.