Workers at a Fiat-Chrysler-owned Mexican factory are threatening to keep up their strike indefinitely in their fight against yellow unionism.

Teksid Hierro staff in Ciudad Frontera, Coahuila, walked out last week after trade union activists were sacked for leading previous stoppages.

The workers went into dispute with the engine-block manufacturer over profit-sharing arrangements when the company declared lower profits despite increased production.

Despite promising no reprisals, the company dismissed Marisol Ruiz, Montoya Guardiola and Oscar Rodriguez Ponce because of their involvement in the strike - including handing out union leaflets.

But the workers were unimpressed with the performance of the company-imposed CTM union after leader Mario Dante Galindo meekly ordered them back to work.

Yellow unions are widely encouraged by the Mexican government and European, US and Japanese companies operating in Mexico.

Over 600 workers have now joined independent union Los Mineros, demanding recognition, better health and safety procedures and more profit sharing.

Los Mineros spokesman Tomas Hernandez Castillo said yesterday: "People are organising a makeshift camp in front of the factory with supplies of water and food and reiterate that they don't want to hear anything more about the CTM."

The overwhelming majority of the strikers have said that they want to be represented by Los Mineros "because it is modern, honest, democratic and especially identified with trade union workers and their families," Mr Castillo said.