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".

OREBRO, Sweden (Reuters) - Swedish police found three rifles in the adult education centre in Orebro where a gunman killed 11 people and wounded several others this week in the country's deadliest mass shooting, a spokesperson said on Thursday.

The attack on Tuesday - described by Sweden's prime minister as the "worst mass shooting" in the country's history - happened at a school for adults.

Police investigating Sweden's worst mass shooting were still trying to establish a motive as to why a lone gunman opened fire at an education campus in the southern city of Orebro, killing 10 people.

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.

While the police say they have not yet identified a motive for Sweden’s worst mass shooting, Reham is alarmed that the man police believe to be the perpetrator attacked a school where Swedish for Immigrants (SFI) courses are taught.

Around 10 people were killed in a school shooting in Örebro. The damage at the crime scene was so extensive that investigators were unable to be more definitive, said Roberto Eid Forest, head of the local police.

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.

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

Swedish police said they were still investigating the motive behind the country's deadliest mass shooting, as local media began reporting details about the gunman. The suspect, named in reports as 35-year-old local man Rickard Andersson,