Four people died of carbon monoxide poisoning after self-made explosives detonated in an illegal mine shaft in south China's Guangxi Zhuang Autonomous Region Thursday.

One rescuer was poisoned by the gas and had been taken to hospital, Guangxi Public Security Department said in a statement.

The blast occurred at 10:30 a.m. inside the mine shaft at Pinggui County, Hezhou City, it said.

Police are continuing their investigation of the incident.