Twenty people were killed in a gas explosion as they tried to reopen an illegal coal mine in northern China that authorities had shut down, state media reported on Monday.
The blast occurred Sunday night as a group of people attempted to extract coal from the mine in Shanxi province, Xinhua news agency said.
The mine near the city of Linfen opened in 2004, but was later destroyed with explosives and sealed up by authorities, the report said.
"Before they could even take out any coal, an explosion occurred, creating a horrible accident," Xinhua said.
The report said search efforts had already ended. It did not say whether the death toll might grow.
Authorities were now searching for the organisers of the illegal mining attempt and investigating the cause of the blast, it said.
The report did not say why the mine had been previously sealed up, but Shanxi has a policy of closing any mines that produce less than 90,000 tonnes of coal per year since many small mines are illegal and unsafe.
China is the world's largest producer and consumer of coal. The rising demand for coal along with the boom in the nation's economy has led to an increase in the number of mining accidents.
China's coal mines took nearly 3,800 lives in 2007, down 20 percent from the year before, the government and state press reported earlier this month.
However, independent labour groups have long maintained that China's mining death toll is much higher than the government says, with local bosses and regional leaders covering up accidents to avoid fines and costly shut-downs.