Negotiators were hoping for a deal this week on farm and industrial trade, so that the talks could be saved.

They were launched in Doha, Qatar, in 2001, but have repeatedly stalled amid deep divisions between rich and poor nations.

'Last chance'

Some officials had described this meeting at the WTO's Geneva headquarters as a last chance for the Doha trade round, noting that the US and other national elections would make negotiations difficult over the next couple of years.

A number of officials described the debate between the US and China and India as one of principle, and not just economics.

Others blamed a lack of courage for the standoff.

"It is a jump in the dark," Celso Amorim, the Brazilian foreign minister, said before final efforts were made on Tuesday.

"You can't calculate until the very last situation all the hypotheses. If you do that [the round], will never finish.

"It will take two years, three years. It will probably be for a new generation," Amorim said.

The issue concerned a "special safeguard" developing countries, led by China and India, have demanded to deal with a sudden surge of imports or a drop in prices.

While farm import safeguards currently exist in rich and poor countries, they are rarely used. The dispute over the proposals concerns the threshold for when developing nations could raise their tariffs, and how high those taxes could rise.

The US had accused the two emerging powers of insisting on allowances to raise farm tariffs above even their current levels.

That violates the spirit of the trade round, the US and other agricultural exporters argued, because it is supposed to help poorer countries develop their economies by boosting their exports of farm produce.