Ten people have been confirmed dead and five injured after a mini-bus plunged over a steep slope in south China's Guangdong Province, said local officials Monday.

The accident happened at about 2:50 p.m. Sunday when the vehicle, which was carrying 33 passengers, swerved and plunged 50 meters down the slope, said an official surnamed Wang, director of the Heyuan Municipal Government information office.

The bus was en route from Gaoguan Township of Lianping County, to Qingchuan Township of Heping County, at the time, he said.

Five people died at the scene and 27 others were taken to two county hospitals, where five of them later died, Wang said.

Five people were still receiving treatment in hospital and one was undergoing abdominal surgery. Seventeen others were under medical observation, he said.

The vehicle was designed to carry 22 passengers, according to an investigation report issued by the municipal Bureau of Emergency Management, which blamed overloading and brake failure as the main causes of the accident.