WARSAW — A 15-year-old former pupil killed one person and injured two others at a Polish school on Thursday, police said, just a day after a 19-year-old wounded 10 people, including himself, in an attack at another school.

“Despite resuscitation efforts, the life of a 37-year-old school employee could not be saved,” police said on X.

Earlier police said they had detained a 15-year-old who entered a school in Leszczydol-Nowiny, in Wyszkow County northeast of Warsaw, at around 9:00 a.m. and wounded three staff members with “a sharp object.”

“Among the injured is the principal, who apprehended the 15-year-old. Police arrived at the scene within minutes of the report, and police operations are currently underway.”

Interior minister Marcin Kierwinski said that in a separate incident in Sierpc in north-central Poland, police detained a 17-year-old who was planning an attack.

They found two knives in his backpack.

Ten people were injured in a knife attack at a school in Ostroleka in northeastern Poland on Wednesday, with police detaining the 19-year-old suspect, who was among those hurt, shortly after the incident.