Norway's anniversary of Breivik massacre

50,000 people attended a concert in Oslo to mark the first anniversary of the gun and bomb rampage by a Norwegian right-wing extremist.

Some 50,000 people attended a concert in Oslo to mark the first anniversary of the gun and bomb rampage by Norwegian right-wing extremist Anders Behring Breivik, which claimed 77 lives.

Prime Minister Jens Stoltenberg earlier led tributes to the victims of the massacre during ceremonies at the two attack sites on the island of Utoeya, and during a church service on Sunday.

Standing in the rain, many of them carrying roses, tens of thousands of people gathered outside Oslo city hall for the tribute concert, which featured US rock star Bruce Springsteen.

Breivik's attack began in Oslo, where he set off a massive bomb outside the main government building, killing eight, before travelling to the island to carry out his shooting spree.

The tribute concert was attended by members of the royal family, including Prince Haakon and Princess Martha Louise. Police put the turn-out at around 50,000.

Stoltenberg, welcoming the crowd, hailed the emergency services and all those who had worked to heal those affected by the killings.

"We had a choice," he said.

"We could have retreated into our homes in fear. And barricaded ourselves behind a wall of mistrust.

"Instead we turned to each other and built bridges of trust...

"We made the right choice. There is no better protection against terrorism than openness, democracy and humanity."

The first to perform was Iranian-Swedish singer-songwriter Laleh, an embodiment of the multiculturalism so hated by Breivik.

Veteran performer Springsteen sang the song that in the 1960s was an anthem for African-American civil rights movement: "We Shall Overcome," and dedicated the song to those who lost loved ones in the attacks.

"For all of us who love democracy and tolerance, it's an international tragedy," he told the crowd.

Stoltenberg at a ceremony on Utoeya, where Breivik gunned down 69 people at a summer camp for members of the Labour Youth League, said: "Let us honour the dead by celebrating life."

The prime minister also met relatives of those killed and laid a wreath on the island.