Nine workers were killed Wednesday in a gas explosion at a coal mine in southwest China's Sichuan Province, local work safety authorities said.

Preliminary investigation showed that 110 miners were working underground when the explosion happened at 10:05 a.m. at the Dashan Coal Mine in Weiyuan County, Lin Shucheng, director of the provincial work safety bureau, told Xinhua by telephone.

However, only 101 of them were lifted to the ground safely, he said.

Rescuers had retrieved the bodies of the nine victims, he said.

The cause of the accident is still under investigation.