About 10 people are dead in a shooting at an adult education center in Sweden

Swedish police said that about 10 people, including the gunman, were killed during a shooting Tuesday at an adult education center. But a final death toll and a conclusive number of wounded hadn’t yet been determined.

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 shooting happened on the outskirts of the city of Orebro, which is located about 200 kilometers (125 miles) west of Stockholm.

Police said that the death toll could rise. Eid Forest told reporters that the suspected gunman was among those killed. Police believe the perpetrator acted alone. He wasn’t previously known to police, officials said.

The school, called Campus Risbergska, serves students who are over age 20, according to its website. Primary and upper secondary school courses are offered, as well as Swedish classes for immigrants, vocational training and programs for people with intellectual disabilities.

Gun violence at schools is very rare in Sweden. But there have been several incidents in recent years in which people were wounded or killed with other weapons such as knives or axes.

Police said that there were no suspected connections to terrorism at this point in Tuesday’s shooting. Eid Forest said there were no warning signs before the attack. Authorities were working to identify the deceased.

Prime Minister Ulf Kristersson will hold a news conference at 7:30 p.m. local time (1830 GMT) alongside Justice Minister Gunnar Strömmer,

Earlier, Kristersson said that it was “a very painful day for all of Sweden,” Swedish media reported.

“My thoughts are also with all those whose normal school day was exchanged for terror,” Kristersson said. “Being confined to a classroom with fear for your own life is a nightmare that no one should have to experience.”

The shooting erupted after many students had gone home following a national exam. Police vehicles and ambulances, lights flashing, blanketed the parking lots and streets around the school as a helicopter buzzed overhead.

Teacher Lena Warenmark told SVT News that there were unusually few students on the campus Tuesday afternoon after the exam. She also told the broadcaster that she heard probably 10 gunshots.

Students sheltered in nearby buildings. Other parts of the school were evacuated following the shooting, which began at around 12:30 p.m. local time (1130 GMT).

Andreas Sundling, 28, was among those forced to barricade themselves inside the school.

“We heard three bangs and loud screams,” he told Expressen newspaper while sheltering in a classroom.