As many as 23 people were trapped after a coal mine was flooded in China's Heilongjiang province Thursday, authorities said.
At least 56 workers were working when the accident occurred in a privately-owned Anzhishun Coal Mine in Jixi city in northeast China, Xinhua reported.
Meanwhile, 33 people have been safely lifted to the ground, Jixi public security bureau said.
Rescuers have been installing pumps to drain the flooded shaft.
The mine owner has been placed under police custody.
However, the cause of flooding remains unknown.