Sweden's worst mass shooting left at least 11 people dead, including the gunman, and at least five seriously wounded at an adult education center west of Stockholm as officials warned that the death toll could rise.

A student at the education centre in central Sweden has recalled how she and others tried to help one of the victims of what would turn out to be the worst school shooting ever to happen in Sweden. "A guy next to me was shot in the shoulder.

The shooting occurred at a center for adult education in the city of Orebro. The suspect is believed to be among the dead, officials said.