LANZHOU - Safety authorities have blamed overloading for a school bus accident that killed at least 19 people, mostly preschool children, in Northwest China's Gansu province Wednesday morning.

The school bus, a van with nine seats, was carrying 64 people when it had a head-on collision with a truck at 9:40 am, the provincial work safety bureau said in a press release.

Of the 19 dead, 17 were children of the Yulinzi Township Kindergarten in Zhengning County, in the city of Qingyang, it said.

Another 45 were hospitalized with injuries, including 13 serious cases, the document said.