Children were injured in the incident at a primary school in the Finnish city of Vantaa, north of Helsinki. A suspected perpetrator was arrested.
The background is still unclear. The incident is being further investigated on site. There were no details yet. The public was asked to stay away from the area. The suspect is also still a minor, according to police. He is believed to be in his early 20s and is still in the country. The cause of the incident is not yet known.