A coal mine gas blast killed seven people and injured three others in southwest China's Guizhou Province, authorities said Thursday.

The accident took place at about 6:30 a.m. Wednesday at the Jiangfeng Coal Mine in Guli Township of Qianxi County, when 52 miners were working underground, said Chen Xiaohui, deputy director of the Guizhou Provincial Work Safety Administration.

A total of six people were killed instantly, and 45 others escaped, of whom three were injured, Chen said. The body of a miner missing after the blast was found Wednesday night, he said.

The injured people are being treated in hospital and are in stable conditions, he said.

The coal mine reports an annual output capacity of 150,000 tonnes. It is equipped with gas monitoring and a drainage system and had just finished a technological upgrade before the accident, Chen said.

The cause of the blast is being investigated, he added.

Source: Xinhua