Anders Behring Breivik, suspect in last Friday's twin terror attacks in Norway that killed at least 93, sits in an armored police vehicle after leaving the courthouse following a hearing in Oslo Monday July 25, 2011 where he pleaded not guilty. / AP Photo/Aftenposten/Jon-Are Berg-Jacobsen
Last Updated 11:13 a.m. ET
OSLO - The man who has confessed to carrying out a bombing and shooting spree that left scores dead in Norway will be held in complete isolation for four weeks after a hearing in which he said his terror network had two other cells.
Anders Behring Breivik pleaded not guilty to one of the deadliest modern mass killings in peacetime, saying he wanted to "save" Europe from the spread of Marxism, multiculturalism and Islamic immigration.
At today's closed hearing Breivik plead not guilty to terror charges over last Friday's twin attacks.
The death toll from the shooting on Utoya island was lowered by Norwegian police Monday morning, from 86 to 68. Police also raised the number of those killed by the bomb blast in Oslo from seven to eight, making the current death toll 76.
At a post-hearing press conference, Judge Kim Heger said the suspect in the bombing of a government office building in Oslo and a youth camp sponsored by the nation's ruling Labour Party explained that he wanted to "induce the greatest possible loss" against the party for its acts of "treason," to prevent further recruitment by the party.
The judge said Breivik claimed to want to send out a "sharp signal" against the ruling Labour Party, and quoted the suspect as saying the party "had to pay price of treason" for the "mass import" of Muslims out to colonize the country.
Judge Heger also said police are investigating Breivik's claim that there are two more cells in his organization.
Heger ordered Breivik held for eight weeks, with four weeks to be spent in solitary confinement allowing no contact with others, including family, to prevent the destruction of evidence.
The judge ordered the hearing closed to the public and press, after Breivik had made clear in an Internet manifesto that he planned to turn his court appearance into theater, Breivik prepared a speech for his appearance in court even before launching the attacks, then requested an open hearing in which he would wear a uniform.
The suspect staged the bombing and youth camp rampage as "marketing" for his manifesto calling for a revolution that would rid Europe of Muslims, he said.
Norwegian broadcaster NRK states that one reason the hearing was closed to media and the public was to prevent possible "coded messages" being broadcast to any Breivik accomplice. Although the suspect appears to be the lone assailant and has confessed to the attacks, police are still investigating the possibility that others were involved.
"It is clear that there is concrete information that a public hearing with the suspect present could quickly lead to an extraordinary and very difficult situation in terms of the investigation and security," Heger said.
Reporters and locals thronged the courthouse on Monday ahead of the hearing for their first glimpse of Breivik since the assault. When one car drove through the crowd, people hit its windows and one person shouted an expletive, believing Breivik was inside.
The hearing ended after about 35 minutes.
The court acknowledged that there was a need for transparency in the case and that it normally would consider arguments from the press when making decisions to close hearings but said that wasn't possible "for practical reasons."
Breivik laid out his extreme nationalist philosophy as well as his attack methods in a 1,500-page manifesto. It also describes how he bought armor, guns, tons of fertilizer and other bomb components, stashed caches of weapons and wiped his computer hard drive all while evading police suspicion and being nice to his neighbors.
Breivik claims in his writing to be part of a new Knights Templar group, and he hints that there may be others waiting to execute similar attacks, though his lawyer said he insists he acted alone.
"Will attempt to initiate contact with cell 8b and 8c in late March," he writes at one point, but doesn't reference them again or explain if these are aliases.
Polish security officials said Monday that he bought some of the components for his bomb-making in Poland, adding that the online purchases were legal. Pawel Bialek, the deputy head of the Internal Security Agency, said Monday that the chemicals can be bought anywhere in Europe. They included a synthetic fertilizer.
Before Breivik's arraignment, CBS News correspondent Jeff Glor reports the shocked capital city of Oslo fell silent for a full minute at midday on Monday, in honor of the victims of the double attack.
Prime Minister Jens Stoltenberg led the mourning nation in a minute of silence on Monday, standing on the steps of an Oslo university next to a flame. The king and queen stood by as well, and neighboring countries Denmark and Sweden also joined in the remembrance.