Fifteen miners were killed, and three others injured, following a mine-car crash Thursday morning in central China's Hunan province, local authorities said.

The accident happened around 12:30 am in Nanyang township of Leiyang city, after six cars of an eight-car carriage carrying 18 miners unhooked and plunged into a tunnel rapidly in the Hongfa Coal Mine, according to the Hunan Provincial Administration of Coal Mine Safety.

The 15 were killed instantly in the crash, while the other three were injured after jumping or being thrown out of the car, according to rescuers.

An initial probe found that the miners had violated safety rules by riding in the mine cars, which are designed to transport coal only. Police have taken custody of the coal mine's managers.

Hongfa Coal Mine is a licensed coal mine.