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.

The suspect, named in reports as 35-year-old local man Rickard Andersson, was reported to be a former student of the school in Orebo, a city 157 km (98 miles) west of Stockholm, where the attack took place on Tuesday. Eleven people died in the shooting, including the attacker, with at least six others injured.

Sweden is reeling days after the country’s deadliest mass shooting left at least 11 people dead, including the gunman, as investigators Thursday continued to look into the shooter's motive. At least five people were seriously wounded in the violence at an adult education center west of Stockholm on Tuesday.