STOCKHOLM — At least ten people have been killed in a school shooting in the central Swedish city of Örebro on Tuesday, according to authorities.

Swedish police said they believe the suspect — a man — to be among the dead. They said the perpetrator acted alone but added the investigation was still in its early stages.

There is currently no terror motive thought to be behind the attack.

"We're working with secret services but as far as I know, it's a person unknown to police," local police chief Roberto Eid Forest said.

He added that authorities could not be "more specific" about the number of fatalities and were working to identify the victims.

The attack took place at the Risbergska school for adults, with those killed found inside the school building, which Forest described as a "big school with lots of space to work through."

Swedish Prime Minister Ulf Kristersson said it was a "painful day for the whole of Sweden," adding that the police operation was ongoing.

"My request is also to now give the police the peace of mind they need to investigate what happened and how these horrific crimes could happen," the leader told Swedish newspaper Aftonbladet.

“The reports of violence in Örebro are very serious. The police are on site, and the operation is in full swing. The government is in close contact with the police, and is closely following developments,” Justice Minister Gunnar Strömmer told Swedish news agency TT earlier on Tuesday.

Swedish media reported earlier that the local hospital had emptied its emergency room and intensive care unit to accommodate the victims.

Students were sheltered in nearby buildings following the attack, as other parts of the school were evacuated following the violence.

The police have urged the public to stay away from the Västhaga area in Örebro or stay in their homes. They also confirmed that no police officers had been injured in the operation.

Local media reported that the Risbergska School was previously a high school converted into a municipal centre for educating adults over 20. Around 2,000 students attend the facility. — Euronews