Beijing: At least 20 people, including 18 pre-school children, were killed and 45 others injured on Wednesday when their overloaded school bus collided with a truck in China's northwestern Gansu province.

The accident took place this morning at Yulinzi township of Zhengning County of the Qingyang city, the provincial work safety bureau said in a statement.

Those injured in the accident have been hospitalized. Thirteen of the injured were in serious condition.

The bureau has blamed overloading for the accident, stating that the bus - a van with nine seats - was carrying 64 people.

The truck from neighbouring Shaanxi Province and was carrying coal. Nearly 70,000 deaths were reported in China last year due to road accidents, according to officials.