Updated

China's state-run Xinhua News Agency says 21 miners who were trapped for four days after an explosion have been confirmed dead. One is missing.

Xinhua quoted Heilongjiang provincial authorities in northeast China as saying the miners' deaths were confirmed on Friday night.

State media reported the mine in the city of Qitaihe was unlicensed and the managers were being questioned.

China is the world's top producer and consumer of coal, and government officials have made a commitment to shutting down unlicensed mines in an attempt to improve safety.

Although the cause of the blast has not yet been identified, such incidents usually occur when unventilated coal gas is ignited by a spark or open flame.