"Russia and China have said they are going to vote for the resolution" on referral to the Security Council, a Western diplomat said.

The diplomat said that if Russia went back on its promise "it would cause a problem in bilateral relations with the United States."

A European diplomat said negotiations among the five permanent Security Council nations on a resolution for the UN watchdog International Atomic Energy Agency (IAEA) had been "very constructive."

"No one tried to chip away for his own position," the diplomat said.

The IAEA's board of governors was meeting in emergency session, with no vote expected Thursday as the United States and Europe continue lobbying for wide support on the 35-nation body. A decision is expected Friday, a diplomat close to the agency said.

Iran has threatened to retaliate if it is hauled before the Security Council by kick-starting sensitive fuel cycle work and blocking international inspections.

But the diplomat said that Iran's continued defiance of IAEA calls on it to stop nuclear fuel work that can also make bomb material has left "people not happy about taking Iran to the Security Council but seeing what the political reality is."

Russia and China made clear to IAEA non-aligned states at a meeting in Vienna Wednesday that they stood strongly behind the resolution, diplomats said.

They said the non-aligneds, which back Iran's right to the peaceful use of nuclear energy, were surprised by the position of the two major Iranian allies and trade partners.

Russian ambassador Gregory Berdennikov told reporters: "We do not object to informing the Security Council of the United Nations about the work carried out by the agency in relation to Iran."

World powers including Russia had agreed Wednesday on the draft resolution.

The United States has sought for two years to win support for taking Iran to the Council, which unlike the IAEA has enforcement powers and can impose sanctions.

The Vienna-based IAEA has been investigating Iran for three years, and in September found the Islamic Republic in non-compliance with the Non-Proliferation Treaty (NPT) for hiding sensitive nuclear activities for 18 years.

Such a finding requires a report to the Security Council but the IAEA held off on this to give Iran time to cooperate with a three-year-old agency investigation and stop nuclear fuel work.

Instead, Iran moved on January 10 to start uranium enrichment and has not fully cooperated with IAEA inspectors, according to an agency report.

Moving the dossier to the Security Council in New York is a "momentous moment," non-proliferation analyst Mark Fitzpatrick told AFP.

"For the first time the Security Council will be able to consider enforcement measures and Iran for the first time will have to face the prospect of paying the cost for the path it is on," said Fitzpatrick, who is from London's International Institute for Strategic Studies think tank.

But a diplomat close to the IAEA warned that referral could provoke Iran to push ahead with a program it insists is peaceful and reduce cooperation with the atomic agency.

The five permanent UN Security Council members (P-5) plus Germany agreed in London on Tuesday to bring Iran before the Council, but in a compromise with Russia put off UN action until at least the next IAEA meeting in March.

Moscow wants time to find a compromise solution.

US President George W. Bush said Wednesday that he backs a Russian plan to have Iran enrich uranium in Russia in order to avoid Tehran mastering this crucial technology, which makes fuel for nuclear power reactors but also bomb material.

The United States, which backed off from calling for immediate Security Council action in order to win a consensus from the P-5, stressed that it was seeking a diplomatic solution.