Suspected internet pirates in 11 countries have been raided in a global operation against illegal distributors of movies, games and software.

Led by the FBI, the search and seizure operation netted copyrighted material worth $50m and led to seven arrests.

Eight servers used to distribute the pirated goods to net users and file-sharing networks were shut down.

Pirated films on offer via the pirate networks included Revenge of the Sith, said US Justice Department officials.

Hidden networks

The raids came out of three FBI undercover operations run out of Chicago, San Francisco and Charlotte in North Carolina.

Many of the groups that operate at the top of the pirating chain, the so-called "warez" groups, are notoriously difficult to penetrate.

Many operate invitation only net communities and, according to the US Attorney General, use encryption, password-protected servers and other techniques to hide what they are doing.

The raids, called Operation Site Down, were carried out in the US, Canada, Israel, France, Belgium, Britain, Denmark, the Netherlands, Germany, Portugal and Australia.

They resulted in four arrests in the US and three in The Netherlands. Those arrested in the US were Chirayu Patel, David Fish, Nate Lovell, and William Veyna.

In a statement about the raids, US Attorney General Alberto Gonzales said that more than 120 leading members of the piracy underground had also been identified during the raids.

Those arrested could face heavy fines or lengthy prison sentences because recently passed US laws impose a maximum 10-year jail term on those that distribute movies and songs before commercial release.

Piracy networks

US Customs and Immigration Enforcement says that 95% of the copyrighted material that ends up on file-sharing networks originates in the "warez" groups.

Pirated goods on offer via the networks included Star Wars: Episode III, as well as business programs such as Autodesk Autocad 2006 and Adobe Photoshop.

"One may wonder whether or not this is simply scraping the tip of the iceberg, but we believe it is very, very important to show the community that we care very much about the protection of intellectual property rights," said Mr Gonzales.

"We have shown that law enforcement can and will find those who try to use the internet to create piracy networks beyond the reach of law enforcement," he said

Some of the "warez" groups busted during the raids included: RiSCISO, Goodfellaz, Hoodlum, Wasted Time, Paranoid, Corrupt, AdmitONE and Hellbound.

The film and music industries have been urging tough action to stop illegal file-sharers on the internet, warning that the huge growth in illegal downloading threatens their survival.

On Monday, the US Supreme Court ruled that software-makers who help people swap music or films over the internet can be sued under certain circumstances.

The Recording Industry Association of America has since filed more than 700 new complaints against individuals sharing copyrighted music and films.