Seven miners working outside the Conchos mine were injured in the blast that occurred in the early hours of Sunday morning while civil protection staff are working to free those trapped in the mine, Reuters reported.
The mine is located in northern Coahuila, a state bordering Texas, and belongs to Mexican company Industrias Mitra.
Army and civil defence specialists have been sent to the mine.
In one of the worst mine tragedies in recent Mexican history more than 150 coal miners died when an explosion collapsed tunnels three decades ago in the same state.