ZHENGZHOU - Seven people have died and 11 others remain missing following a gas explosion early Thursday at a coal mine in central China's Henan Province.

A gas rush hit the Jiulishan Coal Mine in the city of Jiaozuo shortly after midnight, said a spokesman with the provincial work safety authority.

At that time, 18 workers were working underground in the mine, which belongs to Henan Coal and Chemical Industry Group, the province's largest state-owned mining company.

Seven workers have been confirmed dead, and the search for the 11 missing people was hampered by the high level of gas in the mine, the spokesman said.

Rescuers have installed ventilation machines and are speeding up the process of dredging the coal ore which was preventing rescuers from approaching the missing workers.