Legal team for Oscar-winning film director Roman Polanski filed an appeal Tuesday over possible extradition to the U.S. and required a Swiss court to release the famous filmmaker from prison immediately.

The Swiss Federal Penal Court announced that a decision would be made "within the next weeks," and refused to give more information on the case in the meantime. Experts said a swift release was unlikely, and it seems that the director could remain in jail for at least a few months.

The 76-year-old director was arrested at the Zurich airport and is now in custody of the Swiss Justice Ministry. He was there to accept a lifetime achievement award at the Zurich Film Festival last Saturday. The arrest was related to Polanski fleeing the U.S.after pleading guilty in 1977 to having unlawful sex with a 13-year-old girl in Los Angeles.

Switzerland does have an extradition treaty with the United States, but Polanski, as a citizen of France, might have some protection under that country's limited extradition treaty.

His Swiss lawyer, Lorenz Erni, told Reuters Polanski would fight the extradition and while the filmmaker was fine, the detention was very tough for him. Erni declined to comment on how long Polanski might remain in prison.

A Swiss justice ministry spokesman said on Monday it was theoretically possible that Polanski could be released on bail, although that was very unlikely.

The complex extradition process could take years if Polanski challenges it, U.S. judicial sources said on Monday.

French consul general Jean-Luc Faure-Tournaire visited Polanski in jail on Monday and said he was being treated well.

Polanski, known for the 2002 Academy Award-winning "The Pianist," has made a number of popular films which are characterized by violence and sex. He failed to attend the Oscar award ceremony for "The Pianist" at Hollywood for fear that he might be arrested by U.S. law enforcement.