CHICAGO (AP) — Chicago Mayor Rahm Emanuel is turning to a federal appeals court in his increasingly desperate attempt to keep filmmaker George Lucas from building his museum in another city.

Emanuel's office says in a news release Wednesday that it's filing a petition with a federal appeals court to dismiss a lawsuit filed by the parks advocacy group Friends of the Parks, which opposes the lakefront museum.

The announcement comes a day after the wife of the "Star Wars" creator said that the legal fighting over the proposed museum has prompted her and Lucas to start looking for a site in another city.

Emanuel says that if the court doesn't dismiss what he calls a frivolous lawsuit, "the museum will abandon its efforts to locate in Chicago."