An overloaded van taking 12 students home plunged into a 60-meter deep valley in rural southwest China on Saturday.[Photo/yunnan.cn]

An overloaded van taking 12 students home plunged into a 60-meter deep valley in rural southwest China on Saturday, killing?seven people and injuring?seven others, local officials reported.

The eight-seater, loaded with 14 people, rolled into the valley from a mountainous road in the county of Guangnan, Wenshan Zhuang and Miao prefecture of Yunnan province at about 9 a.m., prefecture officials said. The fatality includes the driver, four students, and an elderly man.

Local officials said the van was not a school bus but students in the area usually took the van to commute from home to the school. Many students in the rural boarding school returned home on Saturday mornings.

The eight injured, all students, were sent to the prefecture hospital of Wenshan located more than 3 hours drive from the county for treatment. Their conditions are not immediately known.

Police have launched an investigation into the accident.

It is the second traffic accident involving student fatalities in Yunnan this week, amid a string of fatal school bus accidents across the country that raised national concern over school transport safety, especially in the rural areas.

On Wednesday, two rural primary school students died and another 20 were injured after a horse-drawn wagon they were aboard collided with a truck in Yunnan's Qiubei county.

The government immediately banned farming vehicles, unlicensed buses and vans from transporting students in the county.

Schools are few in the vast and sparsely populated rural areas of China. School buses are themselves relatively new, as children in years past would typically hike rugged roads to attend school.

The issue was thrown into the spotlight after a nine-seat school bus illegally carrying 64 people collided head-on with a coal truck in northwest Gansu province on Nov. 16, killing 19 preschoolers, two adults and injuring 43 others.

Premier Wen Jiabao has called on government departments to "rapidly" draft safety regulations and standards for school buses while further improving the design, production and distribution of the vehicles.

Provincial education authorities in Gansu on Saturday said they have ordered stricter rules for school buses and their drivers and demanded school buses to have Global Position System (GPS) installed to ensure they travel safely.