More than 24 hours after an explosion struck a coal mine in southwestern China, 20 miners are still missing, state media report.
The Xinhua news agency says 35 miners were working at the privately-owned Jinshangou mine when the explosion happened Monday morning; two escaped alive, and 13 have been confirmed dead. (Early reports had suggested 15 deaths.)
Hundreds of rescuers are "working around the clock" to dig through debris and search for survivors, Xinhua reports.
A winch operator who was more than 100 feet away from the entry to the pit was knocked to the ground and injured in the blast, Xinhua reports. But Liu Fixiu said her injuries were "nothing," saying she had a relative working down in the pit when the blast struck. "I hope he is still alive," she told the news agency.
Rescue work is moving slowly out of fear of triggering a second collapse, the news agency reports, and so far gas has been cleared from one tunnel.
More details are hard to confirm: "Local officials did not answer telephone calls from The Associated Press, and a person who answered the phone at the mine hung up when asked about the blast," the AP reports.
"Gas explosions inside mines are often caused when a flame or electrical spark ignites gas leaking from the coal seam. Ventilation systems are supposed to prevent gas from becoming trapped," the AP continues.
The cause of Monday's explosion is under investigation.