Geneva: Marathon talks for a new global trade deal collapsed yesterday after a clash over agriculture between the United States, the world's biggest economy, and emerging heavyweights.

The breakdown came on the ninth day as the United States and India failed to find a compromise on measures intended to help poor countries protect their farmers against import surges, a diplomat said.

"We were so close to getting this done," US Trade Representative Susan Schwab said at World Trade Organisation headquarters.

"The US remains committed to the Doha round. This is not a time to talk about a round collapsing," said Schwab, who looked frustrated and distressed. "The US commitments remain on the table, awaiting reciprocal responses."

However, failure of the talks to find agreement on the core agriculture and industrial goods chapters of the Doha trade round could delay any final accord on trade liberalisation for several more years.

Washington had opposed a push from India, China and Indonesia to secure measures to protect their farmers if faced with sudden surges of cheap farm imports.

The impasse derailed substantial progress that had been made on other agricultural, manufacturing and services trade issues.

As failure looked likely, New Zealand's trade minister, Phil Goff, held out hope for Doha talks continuing at a later date. "I hope... that what we've achieved this week can be used at least to build on as a foundation for the future," he said.

The talks for a global trade began in 2001, shortly after the September 11 attacks in the hope of boosting the world economy and helping poor countries.

They have lurched from crisis to crisis and risk further years of delay without a breakthrough now because of the US presidential election in November and other factors.