It was China's deadliest bus accident in years, said Zhang Guohui, head of the Henan Provincial Work Safety Administration.
Xinhua, China's official state news agency, said 47 people were on the 35-person bus when it caught fire on the Beijing-Zhuhai Expressway about 4 a.m.
The victims were burned beyond recognition and their identities will be determined through DNA testing, the report said.
Officials were trying to find out what caused the fire.
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