Thirteen workers were killed, and five others remain missing after a gas outburst hit a coal mine Tuesday morning in southwest province of Guizhou, local authorities said.

The accident occurred at 7:53 a.m. at the Anping Coal Mine, which is located in the Lihua Township in Libo County, said Min Luming, secretary of the Communist Party of China of Libo County.

Min said 28 miners were working in the shaft when the accident happened. Of them, 13 escaped. Three died later in hospital.

As of Tuesday evening, 10 bodies had been retrieved from the site, while rescuers are still searching for the five missing.

An investigation into the cause of the accident is under way.