Mexico said Wednesday that Canadian company Americas Gold and Silver Corp. was at risk of being stripped of a mining concession in the country's northwest over a labor dispute.

"It shouldn't be understood as a threat... but if the legality is not respected the government can revoke the company's concession," President Andres Manuel Lopez Obrador told reporters.

He said that he would ask Foreign Minister Marcelo Ebrard to explain the situation to the Canadian government.

Lopez Obrador, a left-wing populist, said the row was due to the refusal of Americas Gold and Silver to accept the union chosen by the workers to represent them.

The company owns and operates the Cosala mining project in the state of Sinaloa that consists of 67 mining concessions.

Lopez Obrador said that there was a "bad habit" among some firms of keeping in place subordinate unions that do not defend worker rights.

There was no immediate response from Americas Gold and Silver.

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