A group of Mexican workers at VU Manufacturing has filed a petition under the US-Mexico-Canada trade agreement (USMCA) alleging that the Michigan-based auto-parts maker is pushing them to join a union friendly to the company.

VU workers at the plant on the US-Mexico border had been organizing independently until the company invited the Confederation of Mexican Workers (CTM) into the Coahuila factory to become the employees’ union representative without their consent, the group said Friday in a statement. When one worker complained during a CTM presentation, he was escorted off the premises and fired, they said.

Workers at General Motors Co. voted against CTM in February in favor of a new union after the US filed a dispute against the company over worker conditions in its truck plant in Silao.

CTM and VU didn’t immediately respond to requests for comment Saturday.