How Sweden’s worst mass shooting unfolded at a small town school - and why police have ‘no clear motive’ one week on - IN FOCUS: As Sweden falls silent for the victims of the Orebro killings their families are still waiting for answers,

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."

The police responding to the attack encountered firing so intense that they struggled to tell how many gunmen were on the scene, an official said.

A gunman opened fire at an adult education center in the Swedish city of Örebro on Tuesday, killing at least 10 people in what the country’s prime minister called the “worst mass shooting in Swedish history.

Swedish news outlets identified the shooter as Rickard Andersson, a 35-year-old from Orebro, the city where the shooting occurred, although the police have not publicly confirmed that.

A minute's silence was observed across Sweden on Tuesday to honour the victims of a deadly shooting at an adult education centre in the city of Örebro. The minute's silence was held in Örebro and several other Swedish cities at 12 pm (1100 GMT).