BEIJING - Heavy rain complicated rescue efforts on Sunday afternoon as crews worked to free 19 miners trapped deep underground at a coal mine in South China's Guangxi Zhuang autonomous region.

Zhangcun Coal Mine in Heshan city, Guangxi, was hit by a cave-in on Saturday afternoon that killed three and trapped the others more than 300 meters underground.

Rescuers expressed worries on Sunday that fresh rainfall could cause additional geological hazards or fill the mine with water, Xinhua News Agency reported.