Officials in Sweden have vowed to determine why a man killed 10 people, and apparently himself, in an unprecedented attack that's shaken their "society to its core."

Those are the words of Swedish Prime Minister Ulf Kristersson, following what he described as the worst mass shooting in the country's history, with around 10 people killed. The shooting took place at an adult education centre - located on a campus with other schools - in the central city of Orebro at around 12:30 (11:30 GMT).

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.