A dawn explosion in a Chinese coal mine killed 20 and trapped 17 workers underground yesterday in the country's central region, a national work safety official said.

It wasn't yet clear how far underground the 17 workers were trapped at the state-owned mine, a spokesman with the state work safety administration said.

He had no details on the cause of the 6am blast in Henan province, a couple of hours outside the provincial capital of Zhengzhou, about 430 miles south of Beijing.

China Central Television originally reported that over 30 people were trapped and 20 killed, but the spokesman said the earlier number of people reported trapped included the dead workers.

China's mining industry is the most dangerous in the world, and more than 2,600 people died in mining accidents last year. The Chinese government has shut down more than 1,600 illegal coal mines this year in an effort to improve safety standards.

Henan province was the scene of one of China's deadliest mining disasters on record, a gas explosion in the Daping mine that killed 148 in October 2004.