The US State Department said the proposals fell short of satisfying international demands.

But Russian Foreign Minister Sergei Lavrov said they contained something to work with.

"Based on a brief review of the Iranian papers my impression is there is something there to use," Mr Lavrov said in Moscow.

"The most important thing is (that) Iran is ready for a comprehensive discussion of the situation, what positive role it can play in Iraq, Afghanistan and the region."

The BBC's Bridget Kendall, in Moscow, said his comments left little doubt that Russian and Western approaches to Iran continue to diverge.

Finding common ground for a united response to the latest Iranian proposals may prove tricky, she adds.

US warning

US President Barack Obama warned Tehran earlier this year that Washington wanted to see a positive response to its friendlier overtures by the end of September.

If not, Mr Obama said the US was prepared to press for new sanctions against Iran.

But Mr Lavrov added that he did not think the UN Security Council would support oil sanctions against Iran.

"Some of the sanctions under discussion, including oil and oil products, are not a mechanism to force Iran to co-operate, they are a step to a full-blown blockade and I do not think they would be supported at the UN Security Council," he said.

Details of Iran's latest proposals have not been revealed.

But US State Department spokesman PJ Crowley said on Thursday: "It is not really responsive to our greatest concern, which is obviously Iran's nuclear programme.

"Iran reiterated its view that, as far as it is concerned, its nuclear file is closed. That is certainly not the case. There are many outstanding issues."

He said the six powers negotiating over Iran's nuclear ambitions - the permanent members of the UN Security Council plus Germany - would consult again on Friday.

Iran insists its nuclear programme is for peaceful ends.

State radio, reporting on the proposal on Wednesday, said Iran was "ready to... help ease joint international concerns over the nuclear issue".

On Wednesday, the US envoy to the International Atomic Energy Agency (IAEA), Glyn Davies, said Iran could already have enough low-enriched uranium to produce a bomb, if it was further enriched.