Photo: ReutersAl Jazeera English summarises Monday's developments:
Police in Norway are widening their investigation following a claim by the sole suspect in Friday's killings after he was remanded in custody that he had worked with collaborators.
Up to 150,000 people paid homage in Oslo on Monday evening to the victims of the twin attacks that left 76 people dead. Mourners sang songs and cheered in solidarity while others placed flowers on a memorial wall next to the city hall.
Anders Behring Breivik, a 32-year-old Norwegian man, is accused of carrying out the bombing in Oslo and the shooting spree on the resort island of Utoya.
Jens Stoltenberg, the prime minister, told the crowds in Oslo that Norway would not be defeated by the tragedy.
"Evil can kill a person, but it can never defeat a whole nation," he said, to loud applause.
"With the strongest of all the world's weapons - freedom of speech and democracy - do we set the course for Norway post 22 July 2011," Stoltenberg said.
The original aim had been to hold a memorial procession for those who lost their lives in the bombing and shooting, but the numbers of people were so great that the crowds simply held a mass gathering.
'Two further cells'
Earlier, at Monday's court hearing in Oslo, Breivik said he had "two further cells" in his organisation.
A senior court official declined to elaborate on Breivik's claim after the hearing. Instead, Geir Engebretsen, the court's chief, repeated the ruling of Judge Kim Heger who is trying Breivik's case.
Earlier Heger said: "The accused has made statements today that require further investigation, including that 'there are two more cells in our organisation'."
Breivik had previously said he acted alone in the attacks. Breivik also calmly said in court that that he expects to spend the rest of his life in prison, officials said.
The judge ordered eight weeks detention for 32-year-old Breivik, who has admitted to the attacks. Breivik told the court that he acted to save Europe from Islam.
Heger said that Breivik would be locked up alone with no incoming letters, media nor visitors except for his lawyer. A trial could be a year away.
Breivik had requested his hearing be open to the public in order to "explain fully what he's done, and more importantly, why he did it", Al Jazeera's Harry Smith reported from Oslo.
Breivik's lawyer, Geir Lippestad, told NRK television his client had expected to be shot dead by angry Norwegians on his way to court.
"He has a completely different perception of reality than us other Norwegians, for instance he thinks that torture exists in prisons in Norway," Lippestad said.
But after requests from prosecutors and police to close the arraignment, the judge barred the media and public from attending.
Breivik was arrested under the country's terrorism laws but will not learn the actual charges against him until the investigation is concluded, closer to his trial date.
Jens Breivik, Anders Breivik's father, in an interview with Norway's TV2, said he last saw his son 17 years ago and is horrified by what he has done.
"In my darket moments, I think that rather than killing all those people, he should have taken his own life.
"I feel shame and grief for what has happened. I really wish it was undone," Jens Breivik said.