Three people were killed and another 13 seriously injured after a bus overturned in southwest China's Chongqing Municipality at Thursday noon, local authorities said.

The accident happened on a section of the No. 319 National Highway in Fuling District when something caused the bus to overturn and plunge down a 20-meter-high slope, a Chongqing municipal traffic police department official said.

There were 34 passengers on the bus. Three passengers died at the scene. Ten ambulances rushed 13 seriously injured people to the hospital.

It's unknown whether the driver was injured or dead.

The bus belongs to the Fuling Transportation Co. Ltd. It was on its way from Fuling to neighbouring Wulong County.

The cause of the accident is under investigation.

(Xinhua News Agency February 12, 2009)