ENNISKILLEN, Northern Ireland (AFP) - The European Union and the United States on Monday launched long-awaited formal negotiations on a vast trade pact.

Speaking just before the formal start of the G8 summit in Northern Ireland, British Prime Minister David Cameron said: "We are talking about what could be the biggest bilateral deal in history."

US President Barack Obama said the first round of negotiations would take place in Washington next month.

The negotiations to create the world's biggest free-trade pact will start despite a hard line by France to protect its cherished film and culture sectors from Hollywood.

A EU-US trade deal is touted as a potentially huge boost to business, economic growth and job creation, but the culture issue is seen as potentially offering a bargaining chip to the US side.

Mr Obama said the deal "will support hundreds of thousands of jobs on both sides of the ocean".

"There are going to be sensitivities on both sides... but if we can look beyond the narrow concerns to stay focused on the big picture... I'm hopeful we can achieve (a deal)."

The US president said reaching an agreement "will be a priority of mine and my administration".

The head of the EU executive, Jose Manuel Barroso, speaking at the same news conference, said a deal could create "huge economic benefits".

"These negotiations will not always be easy but I am sure they will be worth it," Mr Barroso said.

"The current economic climate requires us to join forces and to do more with less."