PARIS -- Russia has informed Iran that it will withhold nuclear fuel for Iran's nearly completed Bushehr power plant unless Iran suspends its uranium enrichment as demanded by the UN Security Council, European, American, and Iranian officials said.
The ultimatum was delivered in Moscow last week by Igor S. Ivanov, the secretary of the Russian National Security Council, to Ali Hosseini Tash, Iran's deputy chief nuclear negotiator, said the officials, who spoke on condition of anonymity.
For years, President Bush has been pressing President Vladimir V. Putin of Russia to cut off help to Iran on the nuclear reactor that Russia is building in Bushehr, in southern Iran. The power plant is Tehran's first serious effort to produce nuclear energy and has been highly profitable for Russia. But Putin has resisted.
Recently, however, Moscow and Tehran have been engaged in a public argument about whether Iran has paid its bills, which might explain Russia's apparent shift. The ultimatum might also reflect increasing displeasure and frustration on Moscow's part with Iran over its refusal to stop enriching uranium at its facility at Natanz.
"We're not sure what mix of commercial and political motives are at play here," one senior Bush administration official said in Washington. "But clearly the Russians and the Iranians are getting on each other's nerves -- and that's not all bad."
"We consider this a very important decision by the Russians," said a senior European official. ". . . Fundamentally, the Russians don't want a nuclear Iran."
At a time of growing tensions between Washington and Moscow, US officials are welcoming Russian support on the situation with Iran as a sign that there are still areas in which the two powers can cooperate.