The United States and the European Union 3 of France, Britain and Germany ? the countries pressing Iran hardest on its nuclear programme ? have backed the Russian plan but privately Western diplomats are sceptical Tehran will accept.

Iran says it has a sovereign right to carry out a full nuclear fuel cycle on its own soil but is willing to hear more about the Russian plan. Western diplomats say they believe Tehran is keeping the Russian offer on the table to buy time.

?It?s just window-dressing. We don?t see the Iranians as serious about the proposal,? one EU3 diplomat, who requested anonymity due to the subject?s delicacy, told Reuters.

European officials will make a fresh appeal to Iran to halt sensitive nuclear activities when Iranian Foreign Minister Manouchehr Mottaki visits Brussels yesterday.

Mottaki told reporters at Tehran?s Mehrabad airport on Sunday that he was optimistic about the talks.

?We are ready to hear any new plan ... provided Iran?s right to uranium enrichment is preserved,? he said.

Countries on the board of the International Atomic Energy Agency (IAEA), have called for the Iranian controversy to be referred to the UN Security Council by March 6. The Security Council, where Russia has a veto, has the power to impose sanctions.

Moscow wants to protect its close commercial and diplomatic ties with Iran, where Russian engineers are helping build the country?s first nuclear power reactor in the Gulf port of Bushehr.

Russia says it is as determined as anyone to stop Iran?s hardline leaders acquiring a nuclear weapon and has called on Iran to resume a moratorium on enrichment. Iran started small-scale feeding of uranium gas into centrifuge enrichment machines last week after a break of 2-1/2 years.

With the two countries? borders only 165 km (100 miles) apart, a nuclear Iran would be too close for comfort, say Russian officials. But they also say they are convinced sanctions are not the answer.

<B>Meg Clothier</B>