An explosion in a coal mine on Wednesday trapped at least five miners in northern Mexico, according to Reuters.
The explosion happened around 9 a.m. in Muzquiz in the state of Coahuila, according to civil protection representative Juan Antonio Ibarra.
"We have no information as to whether they are alive or injured," he said, according to Reuters.
The Associated Press reported the number of miners trapped as seven, saying the explosion was caused by methane gas.
Coahuila's top police official said rescue efforts were under way, according to the AP.
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The coal mine was privately operated by Federico Quintanilla, said Ibarra, according to Reuters.
Ibarra said the likely cause of the explosion was a pocket of gas around 60 to 70 meters underground.
The AP noted that methane gas is a frequent hazard in older coal mines, like those in Coahuila.
A methane explosion in 2006 killed 65 miners in another Coahuila mine.