US and EU negotiators launched their 14th round of talks on a mammoth and controversial free trade deal in Brussels on Monday, amid persistent doubts over whether the agreement can be wrapped up by the end of the year as planned.
Once finalized, the Transatlantic Trade and Investment Partnership (TTIP) would create the world's largest free trade area, with around 800 million people. Negotiations began three years ago.
Proponents say TTIP would boost growth and jobs, but critics worry that it could water down consumer protections and make it easier for large corporations to sidestep national laws.
The week-long talks - the third round this year - will involve around 80 to 100 negotiators from each side of the Atlantic. The process is overseen by EU Trade Commissioner Cecilia Malmstrom and US Trade Representative Michael Froman.
The EU side will present detailed proposals on the automotive, cosmetics, textiles, chemicals and engineering sectors, a senior source in Brussels said on condition of anonymity, adding that the US could outline its plans on trade defence issues, among other things.
The aim is to submit a full draft TTIP text following the upcoming summer break, with a view to concluding negotiations by the end of the year, the EU source said, noting that negotiators are working "as fast as we can."
Both sides hope to agree on the outlines of a deal before US President Barack Obama leaves office in January. His successor is due to be elected in November.
But with several of the key issues unresolved, many are sceptical of that timetable.
"While we are mindful of the challenges, we are going to continue to pursue a Transatlantic Trade and Investment Partnership," Obama said Friday in Warsaw, where he met EU President Donald Tusk and European Commission President Jean-Claude Juncker.
"We want to conclude these negotiations before the end of this year, mainly as far as the big blocks of this negotiation are concerned," Juncker added.
The Business Alliance for TTIP, which includes businesses from both sides of the Atlantic, called Monday for the two sides to quickly make "substantive progress."
"A constructive and creative approach is necessary to breach the current gaps in positions," it said in a statement.
Greenpeace, on the other hand, released leaked negotiation documents on energy issues which it said showed that TTIP would leave Germany's push for renewable energy "in mortal danger." The environmental organization has been a leading critic of the trade deal.
Last month's British referendum outcome, in which a majority voted to leave the European Union, has also raised new questions about TTIP. Britain, one of the world's six largest economies, has been a key proponent of free trade within the 28-member bloc.
But the EU source stressed Friday that nothing would change as long as Britain remains a member of the EU - as it will for at least two more years after triggering exit procedures - since it will benefit from all EU trade deals until it leaves the bloc.
Brussels has also negotiated a separate trade deal with Canada which they hope to sign in October, following approval on both sides of the Atlantic. National parliaments across the EU will be able to vet the deal, however, in a move that could delay its implementation.