GENEVA — Trade officials said Tuesday that a high-level summit to salvage a global trade pact collapsed, after the United States, China and India failed to compromise on farm import rules.

Trade officials from two developed and one emerging country told The Associated Press that a meeting of seven commercial powers broke up without agreement at the World Trade Organization on Tuesday.

The officials, who asked not to be named because the news was soon to be announced to a larger meeting of countries, said a U.S. dispute with China and India over farm import safeguards had effectively ended any hope of a breakthrough.

Two officials said WTO chief Pascal Lamy had informed ministers that convergence could not be reached after nine days of talks.

Negotiators were hoping for a deal this week on farm and industrial trade, so that crisis-ridden WTO talks could be saved. They were launched in 2001, but have repeatedly stalled amid deep divisions between rich and poor nations.

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

A number of trade officials described the debate pitting the United States against China and India as one of principle — and not just hard economics. Others blamed a lack of courage for the standoff.

"It is a jump in the dark," Brazilian Foreign Minister Celso Amorim said before final efforts 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."

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

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

The United States 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 U.S. and other agricultural exporters argued, because it is supposed to help poorer countries develop their economies by boosting their exports of farm produce.