A total of 221 miners were underground when the accident at the Dongfeng coal mine occurred at 9.40pm (13:40 GMT) on Sunday, Xinhua news agency reported. It said that the accident was caused by a coal-dust explosion, which knocked out the ventilation systems.

  

Sixty-eight miners have been confirmed dead and 74 have been rescued, Xinhua said, citing sources from the rescue operation.

  

Heilongjiang Longmei Group, a mining conglomerate of four large state-owned coal businesses with a registered capital of 13bn yuan ($1.6bn), owns the Dongfeng mine.

  

The China News Service said the Dongfeng mine was fully licensed.

  

Li Yizhong, the head of the State Administration of Work Safety, and Zhao Tiechui, the State Administration of Coal Mine Safety, were travelling to the site, according to the website.

  

China's mines, many of them illegal, are considered the most dangerous in the world, and the problem has worsened in recent years as demand for raw materials has risen to help fuel the nation's rapid economic growth.

  

More than 6000 miners died in accidents in China last year, according to previously released government figures. Independent estimates say the real figure could be as high as 20,000.