Two of the world’s biggest automakers are butting heads over alleged racketeering involving the United Auto Workers union.

General Motors filed an “unprecedented” federal lawsuit on Wednesday against Fiat Chrysler (FCA) claiming “that its crosstown rival got an unfair business advantage” by bribing UAW officials, reports the Associated Press.

The lawsuit, filed in U.S. District Court in Detroit, “alleges that FCA was involved in racketeering by paying millions in bribes to get concessions and gain advantages in three labor agreements with the union,” the AP says, adding that a federal investigation of UAW corruption “has resulted in multiple arrests.”

The suit specifies negotiations that preceded union contract agreements in 2009, 2011 and 2015.

“FCA was the clear sponsor of pervasive wrongdoing, paying millions of dollars in bribes to obtain concessions” from the union, GM chief counsel Craig Glidden told the AP, adding that “FCA’s manipulation of the collective bargaining process resulted in unfair labor costs … causing harm to GM.”

Glidden says the late Fiat Chrysler CEO Sergio Marchionne as a “central figure” in the conspiracy.

In a statement cited by Axios, FCA said: ”We are astonished by this filing, both its content and its timing. We can only assume this was intended to disrupt our proposed merger with PSA [the French automaker of Peugeot and Citroen] as well as our negotiations with the UAW. We intend to vigorously defend against this meritless lawsuit and pursue all legal remedies in response to it.”

Axios quotes a vice president of the Center for Automotive Research as saying GM’s racketeering case against FCA “is unprecedented.”

Glidden said GM is seeking “substantial damages” in the case, but did not give a specific amount, the AP says. GM promises that any damages it collects “will be invested in the U.S. to benefit our employees and grow jobs,” according to Axios.