Four years after Anders Behring Breivik shot dead 69 people on Utoya island in Norway, about 1,000 Labour Party youths gathered yesterday for the first summer camp to be held there since the massacre.

The right-wing extremist killed mainly teenagers in his rampage on July 22,2011, hunting down participants at a camp of the Labour Party's youth wing (AUF) on the tiny heart-shaped island in the middle of a lake.

Determined to reclaim possession of the site, the youngsters - including a handful of survivors - will hold their annual camp from Friday to Sunday.

Nato Secretary General Jens Stoltenberg, who was prime minister at the time of the attack, was attending the camp and tweeted: "It's good to wake up in Utoya and to be surrounded by so many young activists." Many of the teenagers arrived on Utoya on Thursday, with many pitching their tents near the cafeteria, where Breivik killed 13 youths.

Breivik's shooting spree lasted an hour and 13 minutes, as he methodically stalked and killed so many of the 600 up-and-coming leaders of Labour, Norway's dominant political party, which he blamed for the rise of multiculturalism.