The death toll from a gas explosion in a southwest China coal mine rose to 13, Xinhua news agency said on Saturday, in the latest accident to hit the nation's dangerous mining industry.

Eight other workers were injured, four in a critical condition and one person remained missing, after the explosion that ripped through the Diaoyutai coal mine in Sichuan province on Friday afternoon.

Rescue operations continued on Saturday, Xinhua reported, quoting local authorities.

The cause of the accident was under investigation.

In 2010, 2,433 people died in coal mining accidents in China, according to official statistics -- a rate of more than six workers per day -- but labour rights groups say the true figure may be much higher as mine companies cover up accidents to avoid fines and costly mine closures.