CHANGSHA -- Four people have died and five others are still missing following Wednesday's gas explosion at a coal mine in central China's Hunan Province, local authorities said on Friday.

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The accident occurred at around 9:00 a.m. on Wednesday in the Xinpo (earlier incorrectly reported as Xincheng) Coal Mine of Leiyang City, where 17 miners were working underground. Eight of them were rescued shortly afterwards and the other nine were left trapped, said a spokesman with the local municipal government.

Rescuers have retrieved four bodies of the trapped miners and the other five missing people have slim chances of survival, the spokesman said.

The cause of the accident remains unclear. The privately-owned coal mine produces 30,000 tons of coal annually.