One person has been killed and 10 others injured in an attack at a vocational college in eastern Finland, police have said, as local media quoted witnesses as saying a young man with a sword had burst into a classroom.

The suspected attacker, who was detained, was among those injured. “Officers used firearms during the situation. Police have detained one perpetrator. The injured have been evacuated,” Eastern Finland police said in a statement.

Witness reports in the Finnish media said the suspected assailant burst into a classroom at Savo vocational college in the town of Kuopio on Tuesday morning.

“He hit a girl in the neck with a sword and stabbed her in the stomach,” an unnamed witness told the Keskisuomalainen newspaper. The attacker also set off “some sort of small firebombs”, the witness said.

Another witness, Roosa Kokkonen, who works in a garage opposite the college, told the Finnish TV channel MTV News that a teacher bleeding from her hand had fled from the building.

“While I was helping the teacher, I started hearing other shouts for help. Students were running away and into my garage,” Kokkonen said.

She also told the Finnish news agency STT that students described the weapon as “a long sword”, and that he “started swinging the sword around in the class”.

Police said two of the injured were in a serious condition.

In a tweet, Finland’s prime minister, Antti Rinne, described the attack as “shocking and utterly reprehensible”.