LANZHOU - Seventeen people were injured when a gas explosion rocked a dormitory at a northwest China university on Monday morning.

The blast at 7:32 a.m. at Lanzhou University in Lanzhou, capital of Gansu Province, seriously damaged three floors of a six-floor dorm building.

Fifteen students and two staff members of a nearby hotel were injured.

"I heard a loud bang and saw window panes shatter, the door lock shaken open, and a group of shirtless students rushing out of the building," said a woman surnamed Ma who lives in a neighboring community.

The school administration said the explosion happened as workers were demolishing a building adjacent to the dorm. An initial probe suggests they accidentally damaged gas pipes inside, the local government told Xinhua.

The university has begun its summer holiday, but many students stayed in the dorm for internships, according to the school administration.