DATONG, Shanxi, April 23  -- Twenty-one people were confirmed dead as of Thursday morning, four days after water from a ground-level reservoir flooded a coal mine in the northern province of Shanxi, according to the work safety regulator.

A total of 247 people were working in Jiangjiawan Mine in Datong City when the incident occurred at around 6:50 p.m. on Sunday. Two hundred and twenty-three miners made it out safely, while 24 were trapped.

Rescuers have brought out four of the trapped miners alive from the mine pit, but one of them died in hospital. The other three are receiving hospital treatment. Rescuers have retrieved bodies of the dead miners.

The coal mine, owned by Datong Coal Mine Group, has an annual production capacity of 900,000 tonnes.

The group has ordered all its small mines, many of which were previously privately owned, to suspend production for safety checks.