BBC News with Marion Marshall

About 100,000 people have gathered in the centre of the Norwegian capital Oslo to remember victims of the attacks, which killed 76 people on Friday. Many carried flowers; others hugged each other as they sang hymns. From Oslo, Steve Evans.

Tens of thousands of people, or one estimated 100,000 people, have been walking quietly through the streets of Oslo. Most are carrying flowers, and

occasionally

they hold them aloft

as though

they are torches. People are

congregating

at the edge of the cordoned-off zone where the bomb

shatter

ed buildings, though the barriers have been moved back through the day, leaving a small remaining cordoned area of the worst damage in the city centre. Many more people are congregating at the cathedral in a dense quiet mass of people.

Norwegian police are now investigating the possibility of a wider plot after the man accused of carrying out the attacks, Anders Behring Breivik, told a court he was part of a network, including two other cells. The Prime Minister of Norway, Jens Stoltenberg, has said he believes Norway will be changed by Friday's killings, but it will remain an open and democratic society. Speaking to the BBC, Mr Stoltenberg said he'd been due to speak at the island youth camp the day after the shootings and knew personally some of those who were killed or wounded.

"I knew many of them, and I also knew many of the parents, relatives, friends of those who died. People in Norway are in deep grief. They are still shocked. But we also see a Norway which is very unified and where people are standing together to comfort each other and to take care of each other."