LANZHOU - At least four people were killed and 30 others injured in a road accident on Saturday in Northwest China's Gansu province, local authorities said.

The accident happened around 7:40 am on Qingjia highway in the city of Jiuquan, when a bus from Xinjiang Uygur autonomous region driving east to west overturned and was sideswiped by another bus, the city government announced.

Of the 97 people aboard the two vehicles, four died and 30 others were injured, including 15 in serious condition.

All of the injured have been sent to receive treatment in nearby hospitals.

Further investigation into the cause of the accident is underway.