Ministers from the United States, the European Union, Brazil and India -- the "G-4" -- held a second and final day of meetings in the Indian capital to salvage the Doha talks, billed as a once-in-a-generation chance to lower trade barriers and bring millions out of poverty.

"The Doha Round framework provides for a leadership role for the developing countries, especially India and Brazil. That brings new opportunities along with new obligations," US Trade Representative Susan Schwab said.

A deal between the two biggest trading powers, the United States and EU, and the two leading developing nations, India and Brazil, is seen as crucial to hopes of getting an agreement among the World Trade Organisation's 150 members.

Schwab told reporters she expected no breakthrough in the talks, calling them a "stocktaking" exercise, but added there was now a "sense of urgency" and that discussions were headed in the right direction.

"We have reached 'what if' conversations. Under this format, each country makes conditional offers," she said.

Her comments came as WTO Director General Pascal Lamy said in Geneva that expected lower growth in world trade this year should be a spur for all global players to end the impasse in the Doha Round.

"A successful conclusion to the Doha Round holds great potential for boosting growth and alleviating poverty," Lamy said.

The Delhi talks marked the first time the leading trade negotiating players had assembled for four-way talks since the Doha discussions collapsed last July when Washington refused to yield more ground in cutting farm subsidies.

The talks were also attended by EU Trade Commissioner Peter Mandelson, Indian Commerce Minister Kamal Nath and Brazilian Foreign Minister Celso Amorim.

Schwab sought to allay worries that the WTO needed to come up with agreement before the end of June, when the fast-track trade powers of US President George W. Bush expire.

She said she was confident the US Congress would extend Bush's Trade Promotion Authority, allowing him to implement trade deals without Congressional clearance.

"There is no Plan B -- we have to get an extension," she said.

Mandelson had warned earlier that talks in the Doha round -- launched in 2001 in the Qatari capital -- must be accelerated or "Doha's prospects for this year will be lost."

Developing nations are pushing the US and other wealthy nations to slash farm subsidies, while poorer countries are being squeezed to allow more access to their markets.

India's Nath has said he would prefer no deal to a "bad deal" that did not protect the interests of developing nations.

Australian Trade Minister Warren Truss and Japanese Trade Minister Akira Amari were due to join the session late Thursday, expanding it into a meeting of the "G-6".

India's industry bodies are pushing for wealthy nations to concede more ground on cutting generous subsidies to their farmers.

"An improved offer by developed member countries to reduce their trade-distorting farm subsidies ... is critical to unlock the current impasse," said Habil Khorakiwalathe, president of the Federation of Indian Chambers of Commerce and Industry.