XUZHOU - Three critically injured students died in a hospital in east China's Jiangsu Province early Tuesday, the local government said, bringing the death toll in Monday's school bus accident to 15.

At least eight other children are still hospitalized, said Zhang Bin, deputy head of the Fengxian county government.

He said 16 pupils lost consciousness and were put on life support when they were admitted to two major hospitals in the county late Monday.

The accident occurred at 5:50 pm Monday in Fengxian County. The bus was taking 29 students home when it veered into a roadside ditch and overturned after the driver tried to avoid colliding with a pedicab. Students became trapped at the bottom of the overturned bus and drowned as water gushed into the wreck, Zhang said.

The driver has been detained for investigation, he added.

The vehicle, a Chinese-manufactured Shaolin Auto bus, was registered as a school bus for a primary school in Shouxian township. It was not overloaded when it overturned, officials said.

The accident marks the third serious school bus accident to occur in China in less than a month. The accidents have highlighted the need for a comprehensive overhaul of the vehicles, especially in rural areas, where refitted vans or buses often travel on dirt roads to transport students.

Also on Monday, a school bus carrying 59 pupils was hit by a heavy-duty truck in the city of Foshan in south China's Guangdong Province, injuring 37 students, Cai Yaoxin, an official with Foshan's Lecong township government, said on Tuesday.

Seven of the injured, one seriously, have been hospitalized.

The school bus and truck drivers were put in police custody for investigation, Cai said.

Both accidents occurred only a day after the State Council, China's cabinet, moved to strengthen school bus safety after a deadly crash killed 19 students about a month ago.

A nine-seat school bus illegally carrying 64 people collided head-on with a coal truck in northwest China's Gansu province on November 16, killing 19 preschoolers, two adults and injuring 43 others.

Schools are few in number 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.

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.