Piracy can dent the takings of film studios

Surreptitious videotaping of movies in cinemas would also be outlawed.

The bill's sponsors said unauthorised copying costs film-makers an estimated $3bn (�1.7bn) in lost sales.

The Motion Picture Association of America has tried to restrict leaks by limiting the distribution of DVD previews to awards ceremony judges.

Although it is already illegal to infringe copyright, the bill would make such activity easier to prosecute.

Piracy is costing the film and music industry millions

It would assume that anything posted online before its release date has been downloaded at least 10 times causing damages of at least $2,500 (�1,400).

Illegal copies of movies often end up being sold on street corners and made available through online networks such as Kazaa just after their official release.

This is due to audience members smuggling camcorders into theatres and recording the film.

Another form of piracy takes place when members of the movie industry post films online before their release date.

Criminal offence

If the bill becomes law, the maximum sentence for such practices will be five years plus financial damages charged to first offenders.

Unauthorised videotaping in cinemas is currently a crime in four states and the District of Columbia but is legal in other states.

California Democratic Senator Dianne Feinstein, who is sponsoring the bill with Texas Republican Senator John Cornyn, said there was "no legitimate purpose" for a person putting copyrighted material not legally available to the public online.

The bill was hailed by lobbyists from the movie and recording industries.