Four people died and 20 were injured when a bus and truck collided Sunday in northwest China's Gansu Province, local traffic authorities said on Monday.

The accident occurred at around 10:10 a.m. Sunday, when a bus carrying 22 people from the provincial capital, Lanzhou, to Qingshui county and a truck collided in Maying township of Tongwei county.

Two people died at the scene and another two died en route to hospital.

The injured were taken to hospital. Five people were seriously injured, but were out of danger and stable, a county government spokesman said.

Police are investigating the cause of the accident.

(Xinhua News Agency August 10, 2009)