GENEVA (AFP) – The United States on Friday rejected claims that it is offering too little and asking too much in World Trade Organization talks on tearing down barriers to commerce, saying it was up to others to do more.

Jason Hafemeister, a senior U.S. trade negotiator, took critics within the 149-nation WTO to task for themselves failing propose deep enough cuts in customs duties in farm goods.

"We feel we've made a very strong offer," he told journalists. "It hasn't been responded to, and it's not really a good use of our time to continue exploring strengthening of our offer when we're still very imbalanced with what's on the table."

Farm subsidies and tariffs -- the latter being known in trade jargon as "market access" -- are among the thorniest issues in the WTO's Doha Round talks.

Negotiators have struggled to advance since the round kicked off in the Qatari capital in 2001 with the goal of cutting trade barriers and using commerce to boost living standards in poor countries.

Rich and poor countries repeatedly trade blame for the impasse, which is seen as threatening efforts to finalize a global trade treaty by December. Washington and Brussels also exchange fire frequently.

Pressure is mounting ahead of a meeting of trade ministers in Geneva later this month.

The United States has offered large reductions in farm import tariffs, and says counter proposals from the European Union, Japan and leading developing countries such as Brazil and India do not go far enough.

But Washington has been accused of pushing for unacceptably deep cuts.

On Thursday, senior Indian trade negotiator Gopal Pillai told AFP that the success of the Doha Round hinged on the US being ready to compromise on its hardline position. Hafemeister said Washington was not being stubborn: "We're negotiating in good faith here and trying to address their concerns." However, he said: "We're at a point in the negotiations now where we need to see market access on the table."