About 10 people including the gunman have been killed at an adult education center in what Sweden’s prime minister called the country’s “worst mass shooting.”

Police said they do not know the motive but do not believe it is terrorism, adding they "had no warning sign" about the attack. Officers are working to identify the perpetrator and the victims.

A gunman who killed 11 people, including himself, at an adult education centre in central Sweden may have been a student at the school, police said on Thursday, as they described chaotic scenes after the country's deadliest mass shooting as being like an "inferno".

Sweden’s right-wing government said on Friday it would seek to tighten gun laws in the wake of the country’s deadliest mass shooting at an adult education center where the attacker appeared to have used several of his own licensed rifles.