Peshawar, Pakistan CNN  — 

At least 17 Pakistani students on their way home from a quiz competition were killed in a school van crash on Wednesday, a hospital official said.

Three teachers and the van driver also were killed when the van and a truck collided about 170 miles northeast of Karachi.

More than 10 students were being treated at a hospital in the city of Nawabshah. The youths attended the Bright Future Public School in the town of Daulatpur.