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.

New footage has emerged before a gunman opened fire in a Swedish school which offers language courses for migrants.

Sweden's worst ever mass shooting this week has raised questions about the country's gun laws and widespread gun ownership.

The authorities said that at least 11 people were killed and that the suspect was believed to be among the dead.

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 is reeling from the country's deadliest mass shooting this week as investigators continue to look into the gunman's motive

The king and queen visited the scene of the tragic event that occurred on Tuesday and Swedish flags were flown at half-mast to honor the victims.

Sweden's King Carl XVI Gustaf and Queen Silvia on Wednesday visited the grounds of the education centre where 11 people were killed on Tuesday in the Nordic country's worst mass shooting. (Reporting by Johan Ahlander and Anna Ringstrom,