BEIJING (REUTERS) - A blast at a coal mine in China's far-west Xinjiang province killed 21 people on Friday, state agency Xinhua said.

The gas explosion initially trapped 34 workers at the Baiyanggou coal mine. Thirteen were rescued by Friday afternoon while the rest had died, the agency said, adding that investigations were under way.

Although the toll from accidents has fallen, China's coal mines are the deadliest in the world because of poor safety and the rush to feed energy demand from the world's second-largest economy.

The government plans to shut about 2,000 small coal mines by 2015 to improve safety standards.