Sixteen coal miners have been trapped underground since late Wednesday afternoon following a mine flood in central China's Hunan province, local authorities said Thursday.

Forty people were working underground when the accident took place at about 6 p.m. Wednesday at a mine in Sandu township in the city of Leiyang, a government spokesman said, adding that 24 of the miners escaped safely.

The 16 miners remained in the pit as of 11 a.m. Thursday, the spokesman said, adding that all of the water has been pumped out of the mine.

Rescue operations are still under way.

The cause of the flood is not yet known.