The "safe harbour" protections enjoyed by internet service providers, safeguarding them against liability for copyright piracy, have come under threat from proposals put forward by negotiators to the Acta anti-counterfeiting treaty.
Negotiators are also seeking to give customs officers the right to seize goods they suspect are counterfeit, carry "confusingly similar" trademarks or pirated copies of goods.
Rights holders who stand to benefit from the anti-counterfeiting trade agreement (Acta) have put forward no alternative plans to cut piracy.
The confirmation is contained in correspondence between US senator Ron Wyden and Ron Kirk, the US trade representative, which has just published.
Wyden asked Kirk: "Are you seeking any commitments related to third-party liability for IPR [intellectual property rights] infringements, and if so, what is the outcome that you seek?"
Kirk replied that for a safe harbour approach to be meaningful, "there must necessarily be some form of potential secondary liability against which safe harbour provides shelter".
He went on to say that the US Digital Millennium Copyright Act would be "relevant to US compliance with future Acta obligations".
Acta is being negotiated in secret between the US, the EU, Australia, Canada, Japan, Mexico, Morocco, New Zealand, Singapore, South Korea and Switzerland.
Kirk said Acta was intended to help governments fight counterfeiting and copyright piracy more effectively.
"Trade in these illegitimate goods undermines legitimate trade and the growth of the world economy, and in some cases may contribute to funding organised crime and exposing American consumers to dangerous fake products," he wrote.
Wyden asked Kirk what he proposed to do to lift barriers to inter-industry co-operation to reduce the risk of piracy and to improve policing of abuses.
Kirk replied: "We are not currently proposing any provisions specifically relating to private, inter-industry arrangements." He said he would welcome any suggestions Wyden or other members of Congress might have.
The movie and music industries instigated the negotiations, with the software, electronics and pharmaceuticals industries taking an active part.
Acta forms part of a wider rights holder initiative to gain greater protection against piracy, illegal copying and trade in counterfeit products that is said to cost up to 12% of world trade.
It is complemented by national initiatives such as the UK Digital Economy Bill now in committee in the House of Lords, and the French government's "three strikes" law, which allows alleged persistent illegal file-sharers to be cut off from the internet.
The legislative proposals to curb piracy have been widely criticised for breaking privacy laws, being hard to enforce, and unlikely to stop committed criminals.
Many critics of Acta and the supporting national legislation have called on rights holders to rethink their business model in the light of the ease and speed with which movies, music and software can be copied and distributed, things which also help the rights holders reach their markets quickly and cheaply.
Kirk said his office had set up an Acta page on its new website and sought advice from different stakeholders with an interest in IPR enforcement in the digital world. However, negotiators have consistently refused to give details of the proposals or evidence of the damage that Acta might reduce.
"The administration is committed to continuing to provide opportunities for the public to provide meaningful input into the Acta negotiating process," Kirk said.
The administration also recognised the need for confidentiality to allow officials "to engage in frank exchanges of views", he added.