US Trade Representative Rob Portman, EU Trade Commissioner Peter Mandelson and Brazilian Foreign Minister Celso Amorim said the informal two-day meeting, which was joined by WTO chief Pascal Lamy, had been "candid" without yielding any major breakthrough.

"We do not have yet the contours of a deal, but neither do we have an empty canvas," Mandelson told a joint news conference.

Each representative stuck to his guns in pressing for the concessions that each says others have to make to fulfil the World Trade Organization's "Doha Round" ambition of enriching the lives of millions of the world's poor through freer trade.

Amorim, whose country is a leading player in the G20 bloc of developing countries, stressed that agriculture must come first and foremost in the Doha negotiations.

"We all know we have to have some movement. The question is how much and how," the Brazilian foreign minister said.

"The true negotiation has to be processed in Geneva (at WTO headquarters)."

Brazil, backed by its partners in the G20 bloc, such as India and South Africa, insists the European Union must slash the generous trade protection afforded to its farmers.

Agricultural reform, they argue, would do more than anything else to better the lives of the world's poorest citizens.

But the EU, backed to an extent by the United States, retorts that developing nations must give something in return through opening their markets to more industrial imports and service industries.

Mandelson said that France, which is commonly seen as the staunch defender of generous European subsidies for farmers, was not in fact opposed to agricultural reform but wanted it to take place in a "prudent and managed" manner.

"Our job is to create a sustainable agricultural sector in Europe, not to put farmers out of business," the EU trade chief said.