|Behring Breivik admitted to carrying out the attacks, saying they were aimed at ridding Europe of Muslims [EPA]
Norway has held a commemoration ceremony for the 77 victims of last month's twin attacks.
Some 6,700 people gathered in the Spektrum concert hall in the capital, Oslo, on Sunday in a display of unity, almost exactly a month after Anders Behring Breivik bombed the government quarter before shooting participants at a youth camp on the island of Utoya, some 40km away.
"Nearly all words have been used by now," King Harald V said, as he opened the ceremony.
"These last weeks have been difficult for us but it's doing all of us good to be gathered here today," the monarch said.
Harald said he felt for each person in the country, but that he was certain Norway would surmount its pain.
"I firmly believe that we will uphold our ability to live freely and openly in our country,'' he said.
The ceremony was due to include a speech by Prime Minister Jens Stoltenberg, and a performance by the A-Ha pop group, which was reformed for the occasion.
Between passages of music, Norwegian actors will read aloud the names of the 77 victims, mostly young people, who perished in the attacks on July 22.
The ceremony's audience also included several foreign dignitaries, notably the presidents of Iceland and Finland, Olafur Ragnar Grimsson and Tarja Halonen, all the prime ministers of the Nordic countries, Crown Princess Victoria of Sweden and Prince Fredrik of Denmark.
On the internet, people from around the world joined the commemoration of the victims by participating in a campaign to write Utoya "and shine a light for democracy'' on the social networking site Twitter.
Each time someone mentioned the name of the island on Twitter, the website www.light4utoya.net added a
light to a world map.
On Saturday survivors from the youth camp made a difficult, first return to Utoya, where 69 of their friends were gunned down, in the hopes of finding some closure to their ordeal.
The day before, relatives of the dead were given their opportunity to visit the island where their loved ones spent their last moments alive.
As around 500 relatives made their pilgrimage on Friday, Behring Breivik made a new appearance in court, when a judge ordered him to be kept in solitary confinement for another month in the maximum security jail near Oslo where he is being held.
Breivik, 32, denies criminal guilt because he believes the massacre was necessary to save Norway, claiming it was aimed at purging Europe of Muslims and punishing politicians who have embraced multiculturalism.