The city of Oakland has filed a lawsuit against the Oakland Raiders and the NFL seeking damage for what it classifies as an illegal move to Las Vegas.

The city’s statement on the lawsuit referred to the NFL as a “cartel” and cited a relocation fee that required the Raiders to pay the NFL and its owners $370 million to move to Las Vegas.

The East Bay Times reports that the team and stadium authority were in the midst of negotiations for next year and potentially beyond if delays in the new Las Vegas stadium warranted an extra year in Oakland.

The Raiders have vowed to leave early if the city followed through on its threats of legal action.

“The Raiders demand language that assures them the city will not file a lawsuit against them,” Coliseum authority executive director Scott McKibben previously told the Times.