China says 21 coal miners have been killed and four more are missing following an accident inside a mine in the southern province of Guizhou.

The State Administration of Work Safety said a rescue effort had been mounted. State media reported that another 58 miners safely escaped the accident.

China's mines have long been the world's deadliest, although the government announced last month that the death toll fell by more than 30 percent last year to 1,384 as a result of stricter management.

China is the world's largest producer of coal, which generates about two-thirds of its energy needs.

- AP