Four students of the Wilhelm Dörpfeld Gymnasium, a high school in the German city of Wuppertal, were wounded after a knife attack there on Thursday (Feb. 22).

According to public broadcaster DW, two of the victims were taken to hospital in a critical condition.

Police said that they have arrested a 17-year-old male student who allegedly carried out the attack. North Rhine-Westphalia interior minister Herbert Reul said that the suspect acted alone and that his injuries, which were considered "life-threatening," were self-inflicted.

Police assets were called to secure the scene, and all roads around the school were closed off.

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School Locked Down During Knife Attack

While details of the attack were unclear, one student told German press agency DPA that a friend of his had seen two older students running down the stairs bleeding.

"I thought maybe they were fighting," he said.

All students inside the school at the time of the knife attack were instructed to get inside their classrooms and lock the doors.

"We then pushed the desks in front of the door and sat on the floor at the back," he added. "We were very scared."

Prosecutors said that multiple knives were used in the attack.

The school in Germany's western region specializes in ancient languages and has some 700 students.

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