OSLO - The 32-year-old man accused of horrifying twin attacks in Norway now maintains that two cells of extremists collaborated with him, court officials said yesterday as they ordered solitary confinement for the suspect.

The defendant, Anders Behring Breivik, previously said he had acted alone.

Police also significantly reduced the confirmed death toll in the Friday attacks to 76 instead of 93. It is still one of the worst mass killings in postwar Europe.

It was not immediately clear how police miscounted the number of dead, which happened as rescuers were attempting to tally the victims of the summer camp shooting. The police earlier said 86 had died at the camp and yesterday lowered the number to 68.

They also revised upward the number of dead in the bombing, from seven to eight.

Breivik appeared at a closed arraignment hearing as Norwegians paused for a minute’s silence to mark the deaths.

While acknowledging that he carried out the attacks, Breivik “has not pleaded guilty,’’ Judge Kim Heger told a televised news conference, in remarks translated by an official of the court.

The judge said Breivik had been charged under criminal law with “acts of terrorism,’’ including an attempt to “disturb or destroy the functions of society, such as the government’’ and to spread “serious fear’’ among the population.

Breivik was ordered to be held for the next eight weeks, the first four in solitary confinement. He told police that there were “two further cells in our organization,’’ reporters were told.

Breivik is the only person accused so far in the attacks, in which a huge bomb exploded in central Oslo, followed by a shooting rampage against a camp run by the ruling Labor Party on the nearby island of Utoya.

In testimony, Heger said, Breivik had said he “believes that he needed to carry out these acts to save Norway’’ and Western Europe from “cultural Marxism and Muslim domination.’’

The court appearance was Breivik’s first since he was captured Friday.

Through his lawyer, he had indicated that he wanted to use the hearing as a platform and had wished to appear wearing some kind of uniform. The court rejected those requests.

The judge said Breivik had wished to “give a sharp signal’’ and inflict “the worst possible loss’’ on the Labor Party, accusing it of failing to prevent a “mass importing of Muslims’’ into Norway.

Shortly before Breivik’s arrival, the court said in a statement that the detention hearing should be held behind closed doors.