General Motors is suing Fiat Chrysler, alleging its rival benefitted from bribes to auto union officials that gave FCA an unfair benefit in labor talks, GM announced on Wednesday.

The lawsuit references guilty pleas by former FCA officials, who bribed former United Auto Workers officials, in a long-running case involving a UAW employee training program, that has tarnished the union's image.

The suit comes only weeks after the UAW ended a lengthy strike at GM. The union is currently immersed in labor talks with FCA, the last of Detroit's "Big Three" to negotiate after workers ratified contracts with GM and Ford.

"FCA was the clear sponsor of pervasive wrongdoing, paying millions of dollars in bribes to obtain benefits, concessions, and advantages in the negotiation, implementation, and administration of labor agreements over time," GM said in its announcement. It alleges FCA's actions "corrupted the implementation of the 2009 collective bargaining agreement" as well as "the negotiation, implementation, and administration of the 2011 and 2015 agreements."

FCA dismissed the lawsuit as "meritless" and said it was timed to disrupt the company's proposed merger with French automaker PSA, as well as ongoing talks with the UAW. "We are astonished by this filing, both its content and its timing," FCA said in a statement that also alluded to the company's ongoing labor talks with the UAW.

"We can only assume this was intended to disrupt our proposed merger with PSA as well as our negotiations with the UAW." A spokesman for the UAW said the union contracts were not affected by the bribery scandal but it was "regrettable" the scandal had cast doubt on the process and that the union was committed to cleaning itself up.