Two people were killed and 18 remain trapped underground after an explosion at a coal mine in eastern China, according to reports.
Rescue teams have been battling to reach the stranded workers since around 11pm local time on Saturday, when a rock burst destroyed part of a water drainage tunnel.
There were 334 people working in Longyun mine in Shandong province at the time of the disaster, the official Xinhua news agency said.
Most managed to escape but 22 workers were missing after falling rocks blocked the tunnel.
It was later confirmed two of the 22 were killed in the tunnel collapse. Two others were lifted to safety, leaving 18 trapped underground on Sunday night, said the China Global TV network.
More than 140 firefighters and other specialists have joined the rescue operation, which is being led by Huang Yuzhi, a deputy minister at the ministry of emergency management.
Ventilation has returned to around 200 metres (656ft) of the damaged tunnel, with 50m left to repair, according to officials.
Zhai Minghua, an expert with mine owner Shandong Energy Group, said the rescue efforts were being hampered by the falling of fractured rocks in the tunnel.
The mine was previously run by the county prison but was transferred to the state-owned Longkou Mining Group, a subsidiary of Shangdong Energy Group, in 2016, according to the South China Morning Post.
Rock bursts are a spontaneous, violent fracture of rock that can occur during excavation of mine shafts.
An official with the Shandong Coal Mine Safety Supervision Bureau said the rock burst had nothing to do with workers’ operations.
The cause of the accident is being investigated.
Thirteen miners were killed in an explosion in southern China in August, while at least 38 died in two separate blasts in December 2016.
Additional reporting by Associated Press
