Norway paused today to commemorate the 77 victims of a bomb and gun massacre that shocked the peaceful nation one year ago, a tragedy that the prime minister said had brought Norwegians together in defence of democracy and tolerance.

Anders Behring Breivik, a 33-year-old far-right fanatic, has admitted to the July 22, 2011, attacks: a bombing of the government district in Oslo, killing eight, and a shooting rampage that left 69 dead at the left-wing Labor Party's youth camp on Utoya island.

In a wreath-laying ceremony at the bomb site, Prime Minister Jens Stoltenberg said Breivik had failed in his declared goal of destroying Norway's commitment to being an inclusive, multicultural society.

"The bomb and the gun shots were meant to change Norway," Stoltenberg told a sombre crowd of a few hundred people at the ceremony. "The Norwegian people answered by embracing our values. The perpetrator lost. The people won."

A woman lays down red roses at a memorial site in front of Utoeya Island where members of AUF (The Labour Youth Organisation), guests and relatives of those killed attended a memorial service. (Leonhard Foeger/Reuters)

Tarps were still covering the windows of bomb-damaged buildings on the plaza, and large cement road blocks stop all but pedestrian traffic. Mounted police and officers with bomb-sniffing dogs were on the site, but the security was not overbearing, as if to show that Norway was still an open society.

Survivors and families of victims gathered for a private ceremonyon the island. Eskil Pedersen, a survivor of the massacre and the head of the Labour Party's youth chapter, urged the crowd to renew their commitment to a diverse and egalitarian society.

"Today we remember those who were killed. Tomorrow we continue the fight for what they believed in," Pedersen was quoted as saying by Norwegian news agency NTB.

In a church service attended by government leaders and the royal family in Oslo's cathedral, vicar Elisabeth Thorsen urged congregants to also remember the victims of violence in other parts of the world, including Syria and the U.S., an apparent reference to the shooting rampage Friday that killed 12 moviegoers in Aurora, Colorado.

Thousands of people were expected to attend a memorial concert later Sunday in downtown Oslo.

Youngest victim was 14

The police investigation showed Breivik set off a fertilizer bomb that tore the facade of the high-rise that housed the government's headquarters, and drove toward Utoya unhindered as chaos reigned in the capital.

Anders Behring Breivik, the confessed gunman who killed 77 people last year in a bomb and shooting rampage, grins in an Oslo courtroom June 21, 2012. (Berit Roald/Associated Press)

Arriving on Utoya disguised as a police officer and armed with a handgun and assault rifle, he unleashed a shooting massacre that sent panicked teenagers fleeing into a chilly lake or hiding behind rocks to save their lives. More than half of the victims were teenagers — the youngest had turned 14 five days earlier.

Survivors were gathering for a private ceremony on the island Sunday, while Norway's royal family and government leaders attended a church service in Oslo, where a memorial concert was planned later in the day.

During the 10-week trial that ended in June, Breivik admitted to the attacks, but declined criminal guilt out of principle, saying the victims were traitors for embracing immigration and making Norway a multicultural society.

Prosecutors said Breivik was psychotic and should be sent to compulsory psychiatric care while Breivik's defence lawyers argued that he was sane. The Oslo district court is set to deliver its ruling on Aug. 24.