URUMQI - Six people were killed in a gas explosion at a coal mine in northwest China's Xinjiang Uygur autonomous region on Tuesday, local authorities said Wednesday.

The accident happened at about 6 pm, when six prospectors from the Zhejiang Jinjiang Group Co Ltd. were working in a pit of the Hongshan Coal Mine in the city of Kuitun, according to the safety supervision bureau of the region's production and construction corp.

After overnight rescue efforts, the bodies of all the prospectors were retrieved at 3:35 am on Wednesday, rescuers said.

The coal mine where the explosion occurred is licensed.

An investigation into the cause is underway.