At least 29 miners have been killed in a gas leak at a colliery in south-west China's Guizhou province, state media has reported.
The leak happened on Thursday at the Qunli coal mine in Nayong county.
Fifty-one people were rescued from the mine and another six were missing, Xinhua news agency said. Seven miners were being treated in nearby hospitals.
Officials are investigating the leak and have suspended operations at all county mines pending safety checks.
Two of those hospitalised were reported to be in a serious condition. A rescuer said that chances of finding the six missing miners alive were slim. According to Xinhua, the Qunli mine was a licensed colliery with an annual production of 300,000 tons.
China's mines are among the most dangerous in the world. About 5,000 deaths are reported every year but independent groups say the annual death toll is much higher.
Rising demand for energy and fuel means that owners and local officials often ignore safety issues in pursuit of profits.
In August, 181 miners were killed when floodwater poured into a mine in Shandong province in the east of the country.
The government warned recently that as mines increased output to meet demand in the winter months, more accidents were likely.