The Utoeya shootings are the latest mass killings worldwide perpetrated by lone gunmen:
July 2011: At least 80 killed at a summer camp on the Norwegian island of Utoeya, hours after bomb blast in capital Oslo
January 2011: Six people killed, including a 9 year-old-girl and 11 others injured when a gunman opened fire on an address by US Senator Gabreille Giffords in Arizona. A 22 year old has been charged.
July 2010: Raoul Moat shot his ex-girlfriend, killed her boyfriend,seriously injured a police officer, and went on the run. He shot himself after the manhunt closed in on day 7.
June 2010: Taxi driver driver Derrick Bird killed 12 people and injured 11 others in a wide ranging area in Cumbria, before killing himself the same day.
April 2007: Seung-Hui Cho, 23, kills 32 people and himself on Virginia Tech campus in the US.
April 2002: Robert Steinhaeuser, 19, kills 16 people before killing himself in Erfurt, Germany.
April 1999: Students Eric Harris, 18, and Dylan Klebold, 17, open fire at Columbine High School in Littleton, Colorado killing 13 people before taking their own lives.
April 1996: Martin Bryant, 29, kills 35 people in the seaside resort of Port Arthur in Tasmania, Australia.
March 1996: Thomas Hamilton, 43, kills 16 children and their teacher in a school in Dunblane, Scotland - before killing himself