Seven people were confirmed dead and 23 others were injured when a bus veered off the road and hit a mound on Saturday in northwest China's Shaanxi Province, the local government said.

A brake failure caused the bus carrying 30 people to veer off a country road in Heyang county, dash onto State Highway No. 108, and hit the mound on one side of the highway at 4:30 p.m., a spokesman with the county government said.

He said four people were killed on the spot and three others died in hospital on Saturday night.

The county's health bureau got together the best doctors and nurses from four local hospitals to ensure adequate treatment for the injured, he said.

The victims were all construction workers with the railway authorities in the provincial capital Xi'an and were on their way from work at a railway station along the route linking Xi'an with Hancheng, a city 240 km from Xi'an.

Police have launched an investigation.