The Immigration and Customs Enforcement agency (ICE) is currently targeting owners of websites that violate US copyright laws even if the websites have no direct association with the country, Erik Barnett, the agency's assistant deputy director said, according to the Guardian.
ICE has already courted controversy over its claims that it can apply US copyright laws abroad.
Spanish company Puerto 80 has launched legal proceedings against ICE claiming the agency acted unlawfully by seizing control of two of its sports-streaming websites. ICE cut off access to the sites claiming the content violated US copyright laws despite a Spanish court previously ruling that the sites did not break Spain's copyright laws.
"The jurisdiction we have over these sites right now really is the use of the domain name registry system in the United States. That's the key," Barnett said, according to a Guardian report.
Any website registered with domain name registrar Verisign and which has a generic web address ending like .com or .net web address can be legitimately targeted by ICE, Barnett said, according to the report.
Barnett said that it was legitimate to target website owners whose sites only link to sources of pirated material.
"A lot of drug dealing is done by proxy – you rarely give the money to the same person that you get the dope from. I think the question is, are any of these people less culpable?".
US copyright holders stand more chance of winning a copyright infringement case against a linking website in the US than in the UK, an intellectual property (IP) law expert has said.
Iain Connor, who works for Pinsent Masons, the law firm behind OUT-LAW, said that provisions within the UK's Extradition Act would give the legal means for suspected criminals to be summoned to the US.
The UK-US extradition treaty agreement allows either country to surrender a criminal suspect to the other if the crime carries a minimum punishment of a year's prison sentence.
"US companies are likely to try and secure a conviction in the US where they know that they could succeed on the basis of an offence of 'authorising copyright infringement' which in the UK is not a well defined offence," Connor said.
"The only case where this was looked at was the 'TV-links' case where, based on the criminal burden of proof which requires the person to be found guilty 'beyond all reasonable doubt' rather than the civil burden of proof 'on the balance of probability', it had proved unsuccessful," Connor said.
"It appears that US copyright owners are seeking to rely on the Extradition Act and the US case law to secure a prosecution for the authorisation of copyright infringement by the provision of links to infringing content. Whether this will succeed is no doubt a case that will run and run if the previous case involving Gary McKinnon is anything to go by," Connor said.
Gary McKinnon was arrested in 2002 on suspicion of hacking into US computer systems, including those belonging to NASA and the Pentagon. US authorities have called for McKinnon to be extradited but McKinnon is fighting the summons on medical grounds.
UK student Richard O'Dwyer also faces extradition to the US for alleged copyright offences. O'Dwyer ran a website called TVShack until last year when he took the website down following a visit from police and US officials.
The website provided links to other sites where pirate copies of films and TV programmes could be downloaded. O'Dwyer's lawyers insist that he should only face criminal charges in the UK.
The Government should change the extradition agreement with the US so that the UK courts can intervene to "bar extradition in the interests of justice where conduct leading to an alleged offence has quite clearly taken place on British soil," Isabella Sankey, director of policy for free speech campaigners Liberty said, according to the Guardian.
The public should not be subject to different legal standards on copyright infringement, Jim Killock of the Open Rights Group said, according to the report.
"This seems absurd," Killock said. "If you don't have some idea that there's a single jurisdiction in which you can be prosecuted for copyright infringement that means you're potentially opening an individual to dozens of prosecutions."
Erik Barnett said that ICE was committed to enforcing US copyright laws, and said that copyright pirates were making huge profits from illegal online filesharing activities.
"The general goal of law enforcement is to arrest and prosecute individuals who are committing crimes," Barnett said, according to the Guardian's report. "That is our goal, our mission. The idea is to try to prosecute".
"We seized one bank account for one individual running one sports streaming site. He lives with his parents and has no other source of income. He had $500,000 (£311,013) in his bank account.
"Most of the individuals that we've targeted were earning estimated amounts of between $10,000 and $20,000 a month. You've got to remember that the overheads are fairly low – your product isn't being paid for," Barnett said.