Police say around 10 people have been killed in a shooting at an education centre in central Sweden, including the suspected gunman.

Prime Minister Ulf Kristersson described Tuesday's attack at Risbergska school in Orebro, 200km (124 miles) west of the capital city Stockholm, as the "worst mass shooting in Swedish history".

Police said they believed the male perpetrator to be among the dead and that he was not previously known to them. There was no immediately identifiable motive and he was believed to be acting alone, they said.

"It is difficult to take in the magnitude of what has happened today," Kristersson said at an evening news conference.

Police earlier warned the death toll could continue to rise as several people had been injured.

A number of the injured have been taken to hospital, with at least four people undergoing operations.

Police initially said five people had been shot, and the incident was being investigated as an attempted murder, arson and an aggravated weapons offence.

Local media later began reporting that several people had died, before police said "around 10" people had been killed but they "could not be more specific" about the number of fatalities.

They also confirmed there did not appear to be a "terror" motive behind the attack.

Police heard reports of a shooting taking place at Risbergska school - an adult education centre - at 12:33 local time (11:44 GMT). The facility sits on a campus that is home to other schools.

These centres are attended primarily by people who have not finished primary or secondary school.

Earlier, students at several nearby schools were being kept indoors "for security purposes".

"We don't want members of the public to go there," Orebro police chief Roberto Eid Forest warned.

The justice minister, who appeared alongside the prime minister on Tuesday evening, shared his condolences for those affected by the "tragedy" and reassured citizens that schools in the country would be safe to return to on Wednesday.

"[I've] never seen a school shooting of this magnitude," Gunnar Strommer said.

Nearby hospitals had cleared their emergency rooms and intensive care units to free up space for patients, local media reported.

Orebro University Hospital said five people injured by gunshot wounds were treated at its emergency room. An additional sixth person, not injured by a gun, had "minor injuries" treated, it said.

No children were among the people being treated there, the municipality for Orebro County said in an update.

Teacher Lena Warenmark told SVT, Swedish public radio, she heard around 10 gunshots close to her study.

Ali el Mokad, a relative of a man who is believed to have been studying at the school at the time of the attack, had positioned himself outside of a local hospital waiting to hear on his relatives' condition.

"It doesn't feel very good actually," Mr Mokad told Reuters news agency. He said that his cousin also knew someone at the school, and when she called her friend earlier, "she fell to the ground because she was crying so much".

"She thought what she saw was so terrible. She only saw people lying on the floor, injured and blood everywhere," Mr Mokad said, describing the scene his cousin's friend had witnessed.

Another witness, a student at the school, who gave only her first name, Marwa, described a difficult scene in which she and several others tried to save a person's life.

"A guy next to me was shot in the shoulder. He was bleeding a lot. When I looked behind me I saw three people on the floor bleeding," she told TV4 Sweden.

Marwa and another friend tried to help the injured person by wrapping a shawl around the man's shoulder "so that he wouldn't bleed so much".

"Everyone was so shocked."

Earlier in the day, Prime Minister Kristersson remarked on how today is "a very painful day for all in Sweden" as he shared that those who had a "normal school day" replaced "with terror" are all in his thoughts.

"Being confined to a classroom with fear for your own life is a nightmare that no one should have to experience," Kristersson said in a post on X.

He later asked people to give police the freedom and the space they need to do their work and investigations, as he also stressed that there was no further risks to attending school the next day.

More information will be shared by police and the Swedish government in the coming days, Kristersson added.