A coal mine accident in China’s southwestern city of Chongqing killed seven workers and injured three, state-owned Xinhua news agency reported on Sunday.

The workers at the Fengchun coal mine under the Chongqing Energy Group were killed in an underground transport accident on Saturday afternoon, Xinhua reported.

The group has suspended operations at all of its coal mines, state television reported.

China’s coal mine safety watchdog launched inspections of mines across the country from October to June to improve safety conditions.

The move followed an accident at a coal mine in Shandong province in October that killed eight people, prompting authorities to order 41 coal mines there to halt production for security checks.