SHIJIAZHUANG- A mini van taking primary school students home overturned in north Hebei province Friday, landing six students in the hospital, local authorities said.

The accident happened around 3:20 pm when a flat tire caused an overloaded mini van to overturn on a highway in Gu'an County, said an official from the county's publicity department.

The official said fifteen students had been packed into the van, though it was only designed for eight.

The hospitalized students are all in stable condition, the official said.

The driver said he intended to bring his son home from school but picked up more students after seeing them stranded there by heavy snow. Police have detained the driver and are investigating whether he has run the van as a ticket-selling school bus.

China has promised nationwide safety checks on school buses following a fatal accident in which 21 people, including 19 preschoolers, were killed.

In the November accident, 64 people were crammed on a nine-seat bus before it collided head-on with a coal truck in northwest Gansu province.

The incident sparked national outcry and Premier Wen Jiabao on Sunday urged relevant government departments to quickly create safety regulations and standards for the country's school buses.