The meeting marks the start of what could be a weeks-long process of debate in New York, where the Security Council must find a unified response to the April 28 report by the UN's nuclear watchdog faulting Iran for failing to meet demands to suspend uranium enrichment.
The text of the three Western permanent members' draft proposal has not been seen publicly. But reports suggest that it provides for a clear ratcheting up of pressure on Iran to obey Security Council demands to stop uranium enrichment.Binding Resolution Sought
To date, the Security Council only passed on March 29 a nonbinding resolution calling on Iran to suspend nuclear activities. The three Western permanent members want a new resolution that would now make that call legally binding upon Tehran. They also want Iran's nuclear program to be declared a threat to international peace and security.
The Security Council could take such a step by applying Chapter 7 of the UN Charter, which makes resolutions mandatory under international law. Chapter 7 also opens the way to sanctions and even military action if they are ignored.
Western diplomats have told the media they want any new resolution to set a deadline for Iran's compliance. But they say the Western draft stops short of threatening Tehran with any immediate punitive action, such as sanctions.Seeking A 'Diplomatic Solution'
To build support for such the new proposal, U.S. officials have repeatedly said in recent days that they are focusing upon diplomacy to solve the Iran crisis.
"We have not lost hope in diplomacy," U.S. Undersecretary of State Nicholas Burns told journalists on May 2 in Paris, where representatives of all five permanent member states have held talks this week.
"We believe that there is a diplomatic solution to this problem, but it depends -- it depends on two things: It depends on the willingness of the Iranian government to turn back from a full-scope program to go for [uranium] enrichment, and then, what we believe will be a fissile-material production program and, eventually, nuclear weapons," Burns added.Russian, Chinese Reservations
However, it remains unclear whether Russia and China will support their three Western partners' strategy.
China's ambassador to the UN, Wang Guangya, said on May 2 that he had seen a rough text of the resolution and that "there are some elements that might cause difficulties."
Russia's deputy ambassador to the UN, Konstantin Dolgov, said on April 29 that Moscow sees no reason to use Chapter 7 of the UN Charter against Iran.
Both Russia and China favor negotiations with Iran to solve the crisis. Moscow has previously floated a compromise proposal to allow Iran to do uranium enrichment under supervision in Russia.
But that approach broke down under Tehran's insistence it retain the right to do some enrichment in Iran, and Washington's rejection of any such latitude.Iranian Offer For IAEA
Meanwhile, Tehran says it sees no reason for the Security Council to pass a new resolution.
Iranian Foreign Ministry spokesman Hamid-Reza Assefi called on April 30 for all issues to be referred back to the UN's International Atomic Energy Agency (IAEA). "If the [IAEA] and its board of governors give commitments that Iran's nuclear case will be resolved at the agency, we are ready to cooperate fully with the IAEA," he said.
Tehran, which has said it will not abandon uranium enrichment, says its cooperation would include unfettered access for international inspectors to all its nuclear sites.
As the latest round in the continuing Iran nuclear crisis begins, there are few signs the Security Council can reach a unified position quickly.
Burns told reporters in Paris on May 2 that it could take 30 to 40 days, or even a month or two, to get a new Security Council resolution.
THE COMPLETE PICTURE: RFE/RL's complete coverage of controversy surrounding Iran's nuclear program.
An annotated timeline
of Iran's nuclear program.