ZHENGZHOU - Six people died and 23 others were injured when a mid-sized bus overturned and fell into a river on Wednesday in central China's Henan Province, traffic police said.

The accident occurred around 9:40 a.m. in Luanchuan County, some 300 km southwest of provincial capital of Zhengzhou, police said.

Two people died on the spot, while four others died in the hospital after rescue efforts failed.

A total of 34 people were aboard the bus, which had a loading capacity of 19, sources said.

The injured have been sent to local hospitals and are in stable condition, sources said.

An investigation into the cause of the accident is underway.