The United States is considering dusting off and toughening a year-old offer for Iran to transfer uranium to Russia for further enrichment, a leading French newspaper reported Thursday.

President Barack Obama's administration has shared its latest proposal for diffusing the standoff over Iran's nuclear programme with Russia and China -- although France and Britain are miffed at being left out of the initial communication loop, Le Monde newspaper reported.

If confirmed, the proposal appears to update an offer made last year for Iran to transfer low-enriched uranium for further enrichment in Russia and France to supply a research reactor in Iran.

The only difference would be in the amount -- 2,000 kilos (4,400 pounds) of uranium transferred out of Tehran rather than the 1,200 kilos proposed last year -- according to Le Monde.

Tehran must also agree to relinquish 30 kilos of low-enriched uranium it has accumulated since the beginning of the year, the newspaper said.

Le Monde's report appears similar to one published in The New York Times last week that the Obama administration and its European allies were preparing a new, more onerous offer for Iran than the one rejected by supreme leader Ayatollah Ali Khamenei last year.

According to the Times, the offer would require Iran to send more than 4,400 pounds of low-enriched uranium out of the country, an increase of more than two-thirds from the amount required under a deal struck in Vienna.

France and Britain have dismissed the proposal, Le Monde reported, on grounds it would help legitimise Iran's uranium enrichment programme.

Washington neither confirmed nor denied the report, merely saying that US diplomat Robert Einhorn, cited by Le Monde, has made trips to Moscow and Beijing.

"Our ongoing efforts with respect to Iran have been part of those conversations," State Department spokesman Philip Crowley said. "I'm not gonna go into details about the specific ideas."

France's foreign ministry did not immediately comment on the article.

Le Monde's report comes days after Tehran agreed to resume long-stalled nuclear talks with world powers in a letter sent to the European Union's foreign policy chief Catherine Ashton.

If realized, the discussions would be the first high-level encounter between Iran and the so-called P5+1 that groups the United States, Britain, China, France, Russia and Germany since a round held on October 1, 2009 in Geneva.

The nuclear negotiations aim to address international suspicion that Iran is seeking to develop atomic weapons under the guise of a civilian nuclear programme, a charge Tehran vehemently denies.

Last week, Washington warned Iran's continued uranium enrichment meant any new offer by world powers on its nuclear programme would be more burdensome than one it had already rejected.