Switzerland's top criminal court has granted bail to American film-maker Roman Polanski, accepting a $4.5 million bond as assurance he will remain available for any future extradition hearing.

U.S. prosecutors have asked Switzerland to extradite the 76-year-old Polanski for sentencing on a three-decade-old statutory rape conviction.  He fled Los Angeles ahead of his 1978 sentencing, and remained a fugitive until his arrest in Zurich in September.

In Wednesday's decision, the Swiss court said Polanski would remain under constant electronic surveillance, and that a bracelet alarm would be activated if he leaves his chalet before an extradition hearing.  No hearing date has been announced.

The Academy Award-winning director was initially indicted on several felony counts of rape linked to a 1977 photo session with a 13-year-old girl. He later pleaded guilty to a lesser charge of unlawful sexual intercourse, before fleeing the country ahead of his sentencing date.

Some information for this report was provided by AP and AFP.