Anders Behring Breivik, the gunman who said he was behind the massacre of
76 people, did not plead guilty and was remanded in custody for eight weeks while the investigation into last Friday's twin gun and bomb attacks continues.
As thousands of flower-carrying Norwegians filed through the city centre in an overwhelming show of both grief and solidarity, even Behring Breivik's father said he wished his son had taken his own life.
Norwegian Prime Minister Jens Stoltenberg admitted the country would be changed permanently by last Friday's car bombing in Olso and mass shootings on a nearby island, but vowed to ensure it remains an open society.
He told the grimly defiant crowd massed in the city centre: "Evil can kill a person but it cannot kill a people."
Meanwhile the head of the Norwegian Police Security Service (PST), Janne Kristiansen, said Behring Breivik had been flagged by the authorities back in March because of a purchase from a Polish business selling chemicals, but the incident was too insignificant to warrant a follow-up.
It appeared at the time that "he lived a life that was incredibly respectful of the law."
Behring Breivik had been hoping to use his first court hearing as a platform to explain his actions to the public, but a judge ruled it be held behind closed doors and also barred the suspect from wearing a uniform in court.
Judge Kim Heger said Behring Breivik would spend the first half of his eight weeks in custody in solitary confinement, as police investigate a claim he made during the hearing that he has built an active network of accomplices.
Briefing reporters after the arraignment, the judge said the self-styled Crusader told the court he wanted Muslim colonization of Europe to end.
"The operation was not aimed at killing the largest number possible, but to send a powerful signal that couldn't be mistaken," Heger said.
Before the attack, Behring Breivik wrote a 1,500-page manifesto in which he boasted he was one of up to 80 "solo martyr cells" recruited across Western Europe to topple governments tolerant of Islam.
The suspect also indicated to the judge that he had accomplices who were still at large.
"It appears in the suspect's police explanations and in today's court appearance, he has made statements that require additional investigation -- including a statement about 'two further cells in our organization'," the judge said.
Behring Breivik's 40-minute court appearance came after the country marked a minute's silence which was also observed across Scandanavia.
But that was dwarfed by an evening vigil, where huge numbers flooded into the centre of the capital, many waving red and white roses.
"Tonight the streets are filled with love," Crown Prince Haakon told the vast crowd, which local media estimated at 150,000.
It emerged Monday that the half-brother of Norway's Princess Mette-Marit -- an off-duty policeman -- was one of the victims of the gun attack.
"I think that ultimately he should have taken his own life rather than kill so many people," the gunman's estranged father Jens Breivik said in a Norwegian television interview conducted at his home in the south of France.
Behring Breivik's lawyer Geir Lippestad, meanwhile, said his client had expected to be killed by angry Norwegians when he arrived at court.
"He said several times that he expected to be shot dead," Lippestad told NRK television channel.
A crowd of angry Norwegians hurled abuse at Behring Breivik as he arrived at court, calling him "traitor" and "bloody killer".
Police on Monday said 68 people were now known to have been killed in the shootings at a summer camp on Utoeya island, lowering an earlier toll of 86.
Eight died in the car bombing in downtown Oslo, an increase of one -- but others are still missing, and police said the toll may again rise.
Stoltenberg, who knew a number of the victims on Utoeya, said the massacre would inevitably leave a permanent scar on Norway as society.
"I believe that Norway will change. We will have a Norway before and a Norway after the bomb attack and the killing," he told the BBC.
"But I believe at the same time that Norway will be possible to recognize.
"We will still be a society which is very clear on our values of democracy, of openness and a society where we welcome people to be active, participate in political work in a way where they can feel safe."
The prime minister and King Harald V were among the first signatories to a book of condolence set up at Oslo's main university. The two men were also among the thousands who bowed their heads for a minute's silence.
The country's train stations closed and the stock market halted trading on the stroke of midday. Nordic neighbours Sweden, Finland, Denmark and Iceland held a minute's silence and flew national flags at half-mast.
The reverberations were also felt in Britain where detectives were trying to establish if Behring Breivik had recently visited London.
The attacks have triggered calls for Norway to reinstate the death penalty.
The maximum prison sentence in Norway is 21 years.