An explosion killed at least two people and left an unknown number trapped underground at a coal mine in central China's Henan province on Thursday, state media said, dpa reported.
Rescue workers also found three people seriously injured on the surface after debris from a building collapsed onto them at the Fenghuangling Coal Mine in Henan's Pingdingshan city, the official Xinhua news agency said.
Witnesses said they heard loud bangs and saw several surface buildings collapse after the blast, the agency quoted a local government spokesman as saying.
Rescue work started soon after the explosion was reported at 5:30 am (2130 GMT Wednesday) but safety officials were still trying to determine the number of miners underground and the cause of the blast, the report said.
Last month, an explosion killed 49 miners at an illegally operated coal mine in Pingdingshan.
Accidents kill thousands of people annually in Chinese coal mines. The accidents are often triggered by outdated equipment and poor safety measures, many of them at illegal mines.