Film director Roman Polanski, shown in January, has been denied bail by a Swiss court pending his possible extradition to the U.S. (Michel Euler/Associated Press)

The Swiss government says the United States has formally requested the extradition of imprisoned director Roman Polanski on 1977 charges for having sex with a 13-year-old girl.

The Swiss Justice Ministry said the United States filed its request late Thursday and that it has been forwarded to Zurich authorities for an extradition hearing.

Polanski may appeal the decision if the extradition request is approved, the ministry said in a statement Friday.

The 76-year-old director has made a number of appeals to be released on bail, but has been denied because both the ministry and court felt he was too great a flight risk.

The Oscar-winning filmmaker behind The Pianist, Rosemary's Baby and Chinatown fled the U.S. in 1978, a year after he pleaded guilty to unlawful sexual intercourse with a 13-year-old girl in 1977. Lawyers for Polanski have claimed misconduct by the now deceased judge who arranged his plea bargain and then reneged on it.

The director has asked a U.S. Appeal Court in California to overturn a lower tribunal's refusal to throw out his case.

The victim, Samantha Geimer, identified herself publicly and has since joined in Polanski's bid for dismissal, saying she wants the case to be over.

Previously, she had sued and reached an undisclosed settlement with the director, who has lived in France for the past three decades.

With files from The Associated Press