"The story is not accurate. There was no offer," Richard Mills, a spokesman for US Trade Representative Rob Portman, told AFP.

Diplomats at World Trade Organisation headquarters in Geneva said the offer was made to Portman by EU Trade Commis-sioner Peter Mandelson at a meeting in London on Thursday also attended by ministers from Brazil and India.

Brussels stands ready to lower tariffs on agricultural produce if Washington cuts subsidies to American farmers, the EU official was said to have proposed.

Mandelson called the meeting ahead of a conference of around 30 leading WTO members next week in Dalian, China, which will attempt to spur sluggish negotiations on an international trade treaty.

"Mr. Mandelson said he was ready to make a move on market access if there is specific language commiting the United States to make substantial efforts on counter-cyclical payments and on cotton," one diplomat in Geneva said.

Portman did not react to the offer, but Brazilian Foreign Minister Celso Amorim said it could generate the trade-off needed to energize the difficult WTO talks, diplomats said.

But Mills said: "The US side denies reports out of Geneva related to the meeting in London."

Farm trade represents only 13 percent of world commerce in goods, but is nonetheless seen as key to a successful conclusion to the WTO's Doha Round of trade talks, which was launched in the Qatari capital in 2001.