A gas explosion occurred Saturday in a coal mine in Fuyuan, a mountainous county in southwest China's Yunnan Province, with fatalities estimated at more than 20, local sources said.

The coal mine explosion took place at about 5 p.m. on Saturday at Housuo Township of Fuyuan, three and a half hours' bus ride from Kunming, the provincial capital of Yunnan. The sources said the blast may have killed more than 20 miners and injured over 20 others.

The cause of the gas explosion is under investigation and rescue operations are going on.