Attorneys for the US District Court for the Northern District of Illinois said they want 30-year-old Kharkiv-resident Artem Vaulin - who was arrested in Poland on Wednesday - to be extradited to the US to face charges that include conspiracy to commit criminal copyright infringement and money laundering.

US officials will seek to extradite Vaulin to face charges filed in federal court in Chicago, which has reportedly ordered the seizure of a bank account and seven domain names connected with the website.

"Vaulin is charged with running today's most visited illegal file-sharing website, responsible for unlawfully distributing well over $1 billion of copyrighted materials," Assistant Attorney General Leslie Caldwell said.

The move comes as the founder of Megaupload - known as Kim Dotcom - is fighting extradition to the US from New Zealand. He denies allegations his site has cost film and record companies over $500 million (454 million euros) in revenues.

Vaulin was allegedly involved in designing the original "Kickass Torrents" (or KAT) website and has allegedly run it since 2008 through a Ukrainian-based front company called Cryptoneat. KAT has reportedly overtaken "Pirate Bay" and others to become the world's biggest source of pirated media.

KAT has moved its domains several times after being blocked in the UK, Ireland, Italy, Denmark, Belgium and Malaysia, according to the complaint, and has relied on a network of computer servers located around the world, including in Chicago.

"Copyright infringement exacts a large toll, a very human one, on the artists and businesses whose livelihood hinges on their creative inventions," US attorney Zachary Fardon said in a statement. "Vaulin allegedly used the Internet to cause enormous harm to those artists," Fardon said, adding that KAT relied on computer servers around the world due to efforts to halt illegal file sharing.

There was no legal representation listed for Vaulin in any court docket, a US Department of Justice spokesman said.

US officials allege that KAT - operating in 28 languages - has a net worth of over $54 million.

The complaint stated the site has illegally made available for download movies that were still being shown at movie theaters such as "Independence Day: Resurgence" and "Finding Dory."

Officials also allege the peer-to-peer file-sharing website had, since 2008, distributed copyrighted works for financial gain - such as this year's film "Captain America: Civil War."

jbh/gsw (Reuters, AFP)