At least 38 people have been killed when a van carrying inflammable liquid hit a bus on a highway in central Chinay.
The collision in Hunan province triggered a fire and explosion which destroyed five vehicles.
Another five people were injured in the accident which occurred at around 3am.
The fire was finally put out by about 8am.
The long-distance bus, with capacity for 53 occupants, was travelling between the eastern coastal province of Fujian and Guizhou in the southwest when the crash occurred.
Senior work safety and transport ministry officials and police were heading to the site to investigate.
Fatal traffic accidents are a serious problem in China, where the road network and number of new drivers are expanding rapidly.
The ministry of transport says the number of road deaths in China fell from 104,000 in 2003 to 60,000 in 2012, or from about 300 fatalities a day to less than 200.
A study published in 2011 by a group of Chinese and US researchers concluded, however, that the number of deadly accidents was two times higher than the police claimed.