A Chinese state news agency is reporting that a gas explosion at a southwestern coal mine has killed 14 miners and injured four.

Xinhua News Agency said Saturday that investigators are looking into the cause of the Friday night blast in Yunnan province.

China's mines are the world's deadliest, where explosions, cave-ins and floods killed nearly 3,800 people last year.

Coal accounts for about 70 percent of electricity production for the booming economy and efforts to improve safety have been frustrated by lax enforcement, week safety regimes and corruption between local officials and mine owners chasing fat profits.