Leader of AUF Party in Norway and a survivor of the 2011 shooting, Astrid Hoem, Prime Minister of Sweden Stefan Lofven and a leader of the Norwegian Labor Party Jonas Gahr Store lay flowers at the memorial on Utoeya island the day before the 10th anniversary of the terrorist attack, in Utoeya, Norway July 21, 2021 Beate Oma Dahle/NTB/via REUTERS OSLO (Reuters) - Norway on Thursday marks 10 years since anti-immigrant extremist Anders Behring Breivik killed 77 people in the worst act of violence in the country since World War Two. Breivik detonated a car bomb outside the prime minister's office in Oslo, killing eight, before driving to Utoeya island and shooting 69 people at a Labour Party youth camp on July 22, 2011.