"But this hate, it is coming from somewhere." A member of Kasselia's congregation, 29-year-old Salim Iskef, was among those murdered in Orebro on Tuesday in Sweden's first school shooting and the worst mass shooting in the country's history.

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.

Salim Iskef, 29, fled the Islamic State and Syria to form a better, more secure life in Sweden, only to be gunned down this week in the worst mass-shooting in Swedish history.