OSTROLEKA, Poland (AP) — A 19-year-old student at a vocational school in northern Poland attacked fellow students, teachers and passersby with a sharp object Wednesday, injuring nine people before fleeing and being arrested nearby, authorities said.

The attack took place about 11 a.m. local time at the Vocational School Complex No. 4 in Ostroleka, about 120 kilometers (75 miles) northeast of Warsaw, police said. Authorities did not provide any information about the suspected motive, or details about the weapon.

Five students, two teachers and two passersby were injured, regional Gov. Mariusz Frankowski said. None of the injuries were life-threatening, but one person was seriously wounded and some victims were evacuated by helicopter to a hospital.

Authorities identified the suspect only as Jakub Z., in line with Polish privacy laws.

He was arrested on a riverbank less than 1 kilometer (a half mile) from the school after fleeing the scene, according to police. He was wounded at the time of his arrest in what prosecutors said was a result of “self-mutilation.” The young man was taken to a hospital.

Police in the Mazovia province, which includes both Ostroleka and Warsaw, posted a photo on X showing a policeman with his hand placed on the back of a person lying down with their hands tied behind their back. The person’s face and hands are pixelated.

Polish media published blurred photos reportedly taken by students that showed bloodstained floors inside the school.

Two hours after the attack, Ostroleka Mayor Paweł Niewiadomski wrote on social media that the “situation has been brought under control” but that the school would remain closed while authorities investigate the circumstances of the attack.

He said kids and others affected would receive psychological support and that he had asked all schools in the region to ban any unknown people from entering their premises.

A spokesman for the local firefighters told Polsat television that a suspicious backpack was found in the school and that authorities were investigating its contents.

Police said the suspect had previously come to their attention over the possession of a small amount of narcotics.

School attacks are not common in Poland. However, a stabbing at a Catholic convent in southeastern Poland last month left one person dead and four others wounded. Police detained a suspect.

——- Ciobanu reported from Warsaw, Poland.