18 people have been killed, and another two remain missing after an explosion occurred in a coal mine in northwest China's Ningxia Hui Autonomous Region.

Rescuers prepare to go down the coal mine for rescue work in Shizuishan City, northwest China's Ningxia Hui Autonomous Region, Sept. 28, 2016. Eighteen miners have been confirmed dead while two others remain missing after an explosion occurred on Tuesday morning at a small coal mine belonging to Linli Coal Mining Co. Ltd. in Shizuishan City. An initial investigation showed that the deadly coal mine explosion was caused by illegal mining. (Xinhua/Wang Peng)

At the time of the explosion on Tuesday, one death was reported, and 19 others were believed to be trapped. But in following search and rescue operation, 17 bodies were found.

Authorities are still searching for the missing two. A working team led by the deputy chief of National Coal Mine Safety Supervision Bureau is at scene to lead the rescue operation.

Initial investigations indicate illegal mining activities, and the person in charge of the mine is now under police custody.