A former student opened fire at a high school in southeastern Turkey on Tuesday, wounding at least 16 people, before killing himself, an official said.

The 18-year-old attacker, armed with a shotgun, fired randomly inside a vocational high school in Siverek, Sanliurfa province. He later killed himself with the same shotgun after being “cornered by police,” Gov. Hasan Sildak said.

The attack left 10 students, four teachers, a canteen employee and a police officer hurt, Sildak said. While most of them were being treated in Siverek, five of the teachers and students were transferred to a hospital in the provincial capital because their conditions were more serious, the governor said.