Three workers were killed and another 11 were trapped and feared dead after an explosion on Tuesday at a small coal mine in northern Mexico.
Workers lost contact with their colleagues immediately after the explosion in the desert state of Coahuila near Texas, where small-scale coal mining is a risky way of life in an impoverished region.
Late on Tuesday, rescue workers found three dead miners after they went down into the mine to check if a rescue effort was possible given the high levels of methane and the mine's simple wooden structure surrounded a small metal derrick.
Labor Minister Javier Lozano said three miners had been confirmed dead. "It doesn't look good," he said of the others who were trapped.
Speaking from the mine site several hours drive northwest of Mexico's third-largest city Monterrey, Lozano said Chilean miners were due to arrive on Wednesday to help with the rescue effort.
Rescue workers warned the trapped miners would be dead unless they were trapped in a pocket with breathable air.
"We can't hear anything, we can't see anything," Jesus Montemayor, the mayor of the nearby town of Sabinas, said of the mine. He said the explosion was felt for miles around.
A boy who was working at the site lost his arm in the blast, Lozano said, adding the mine had been operating for 20 days but that no one from the mine company was on site.
Small coal mines are partially supported by the Mexican state, which buys coal for power generation from the facilities that are often located in very poor areas of the country.
The bulk of Mexican coal consumption is supplied from domestic sources although imports have increased in recent years as coal-fired power generation increased.
Mexico's worst mining accident in recent years occurred in 2006 at Grupo Mexico's Pasta de Conchos coal mine where 65 workers died following an explosion.
Families of the victims are pressing for a renewed effort to recover the 63 bodies that are still trapped in the mine.
The Pasta de Conchos accident deepened the mistrust between Grupo Mexico and organized labor in the country, and unions have pushed for improved safety regulations at Mexican mines.
"The national miners union completely rejects the security conditions in which coal miners work in Mexico," the union said in a statement after the accident.
Grupo Mexico and other miners say they operate safely.