The controversial Transatlantic Trade and Investment Partnership (TTIP) has been thrown into further doubt after a senior German minister claimed the United States was not willing to make "any serious concessions".
Agriculture Minister Christian Schmidt is the latest senior European politician to criticise the American approach to the negotiations, which Barack Obama had hoped would be completed this year.
Mr Schmidt told German newspaper Der Spiegel: "So far at least they have hardly made any serious concessions."
He said US negotiators were mistaken if they believed "they can lure us Germans with concessions in the automotive sector."
In reference to potential concessions in one industry for agreements in another, he added: "We won't sacrifice our high food safety standards in a barter trade for approval of European car blinkers."
French President François Hollande has said France would reject the deal in its current form as they opposed "unregulated free trade".
Chancellor Angela Merkel has reiterated the government line, stating she would "do everything to conclude the negotiations" before the end of this year.
Despite David Cameron's denials, campaigners claim the TTIP could lead to selling off of the NHS by breaking down protections of public services.
Mr Cameron said: "There are plenty of reasons that people don’t want to see trade expanded.
"I think they should be honest about it and say they don’t like trade deals rather than using the red herring of the NHS to distract from a trade deal that could add tens of billions to our economy and generate jobs."
