Mexico's mining union said it began a 24-hour nationwide strike on Monday in a dispute over the reelection of union leader Napoleon Gomez.

Some 70,000 miners could join the stoppage, union official Carlos Pavon said. He said 90 percent of union members were reporting that they had laid down their tools early in the morning.

All of the sections, all over the country, are not working, Pavon told Reuters.

The union is demanding the labor ministry confirm the reelection earlier this month of Gomez as head of the union. Gomez is currently living in Canada to avoid arrest on charges of corruption -- allegations he denies.

Grupo Mexico's giant Cananea copper mine is already closed due to a months-old labor dispute but the strike may affect production at Mexico's largest silver miner Fresnillo , a subsidiary of Penoles

Mexico's third-largest steal company AHMSA said it was not affected by Monday's stoppage and everything was operating normally at its plants.

The Mexican mining chamber published a full page advertisement in various Mexican newspapers denouncing the 200 strikes staged by workers over the last eight years.

The only point of this latest threat is to hold us hostage to resolve an internal conflict within the union that has nothing to do with the companies, the statement said. (Reporting by Mica Rosenberg and Gabriela Lopez in Monterrey; editing by Walker Simon)

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