Russia has told Iran that it will withhold nuclear fuel for a power plant Moscow is building inside the Islamic republic, unless Tehran halts its contentious uranium enrichment program, according to a Tuesday report in the New York Times.
The ultimatum comes after several weeks of growing tension between Tehran and Russia, one of the few countries that has tried to temper a push by the United States to punish Iran for its nuclear program.
Russia has been building a nuclear power plant at Bushehr, in Iran, as an incentive to deter the regime from forging ahead with a nuclear enrichment program on their own, away from the eyes of other nations.
In recent weeks, Moscow has accused Tehran of failing to make payments for the crucial fuel delivery — what would be the next step in the plant's construction — and said the fuel would be withheld until overdue payments were made.
Russia's state-run nuclear power company went so far as to say the delinquent payments could permanently derail the planned construction of the plant.
Iran's government has insisted repeatedly that all due payments have been made, and says Russia must provide the gas according to the deal struck by the two nations.
U.S. and European government representatives said Tuesday that Russia is pulling out its experts from the Iranian nuclear reactor site at Bushehr.
The representatives a European diplomat and a U.S. official said a large number of Russian technicians, engineers and other specialists have returned to Moscow within the last week. They spoke to The Associated Press on condition of anonymity because their information was confidential.
Russia's new ultimatum was delivered last week by Igor S. Ivanov, the secretary of the Russian National Security Council, to Ali Hosseini Tash, Iran's deputy chief nuclear negotiator, according to The Times, which cited anonymous officials.
It indicates a shift in the Russian attitude towards Iran that diplomats in the U.S. and Europe will welcome.
Western members of the U.N. Security Council have been pushing for much harsher sanctions against Tehran to force them to halt enrichment, but they've met with resistance from Russia and China, both of which wield veto-power in the council.
"We're not sure what mix of commercial and political motives are at play here," one senior Bush administration official told The Times. "But clearly the Russians and the Iranians are getting on each other's nerves — and that's not all bad."
It wasn't clear whether the Russians adopted their new, tougher stance on Iran over the money issue, or for reasons related to the constant pressure applied on Moscow from Washington and Europe to force Iran's hand.
Meanwhile, South Africa called Monday for a on sanctions against Iran and said a resolution drafted by six world powers should drop an embargo on arms exports and financial sanctions targeting Iran's Revolutionary Guards and an Iranian bank.
The proposals by South Africa, which holds the rotating presidency of the U.N. Security Council this month, were obtained by The Associated Press ahead of an informal council meeting Tuesday and the first formal discussion Wednesday on the draft resolution.
The U.S. has granted Iranian President Mahmoud Ahmadinejad a visa, letting him travel to New York to address the U.N. Security Council as it considers sanctions against Tehran over its nuclear program.
The department has processed 39 visas for Ahmadinejad and his delegation, which includes 12 other senior Iranian officials and 26 security guards, he said. Another 33 visa requests, for airline crew and support staff, are expected to be processed shortly.
The approvals, which had been expected, were announced Monday after world powers agreed in principle to the new sanctions. Iran wants to speak to the council before members vote on the resolution to impose the new measures.
© 2007 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.