AKIPRESS.COM - Twenty-one miners who were trapped for four days after an explosion hit their unlicensed coal mine have been confirmed dead, and four people have been arrested in connection with the disaster, state-run Xinhua News Agency reported Saturday.

Among the four suspects are the mine owner and three managers, the emergency rescue headquarters said in a statement carried by Xinhua.

One miner is missing in the city of Qitaihe in Heilongjiang province in northeast China, and the rest of the bodies were retrieved on Friday night, Xinhua said.

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.