The United States and allies Canada and Britian held informal meetings Monday evening to get other countries to sign on to the resolution after the head of the International Atomic Energy Agency (IAEA) said earlier Monday that Iran must declare all its nuclear activities, diplomats said.
"I'm going to strongly urge Iran to clarify all issues relevant to its enrichment program to make sure that all its enrichment activities have been declared and are under... verification," IAEA Director General Mohamed ElBaradei told reporters as the agency's 35-nation IAEA board of governors began several days of meetings.
An IAEA report had disclosed before the board meeting that Iran had components contaminated with highly enriched, possibly weapons grade, uranium particles.
ElBaradei said the Iranians had to prove their claim "that there have been no uranium enrichment actitivites in Iran involving nuclear material," according to a copy of the report obtained by AFP.
He said Monday that Iran must also resolve questions about having tested gas centrifuges which could be used to produce weapons-grade uranium.
IAEA inspections which began when ElBaradei visited Iran in February are continuing and another report is to be filed in November, officials said.
The United States has backed off on calling for the IAEA to sanction Iran for non-compliance with the nuclear Non-prolifeation treaty (NPT), a move which would force the issue into the UN Security Council.
A Western diplomat said that since there was no proof Iran had diverted uranium from peaceful uses and since Iran has not thrown out IAEA inspectors, as North Korea has, there was "no legal basis for determining the country is in non-compliance."
In Washington, State Department spokesman Richard Boucher said Washington hoped the IAEA would adopt "the strongest possible resolution" calling for Iran to comply with its commitments under the NPT.
The United States, Britain, Canada and Germany are sponsoring the resolution demanding Iranian compliance and which they hope the board will adopt unanimously, diplomats said.
A Western diplomat said that while Washington would like to see a deadline set for Iranian compliance it was willing to let this point drop in the face of opposition from non-aligned countries, and apparently Russia.
"What's important is that the board remains seized of the matter, that a signal is sent, that a clear bright line is laid down that Iran must comply with IAEA requests in a quick, complete and transparent manner," the diplomat said.
Another diplomat said an "unwritten deadline" for Iran to provide the necessary details on its program could be when the IAEA board meets again in November.
ElBaradei said Iran, which is an IAEA board member, should also sign an additional protocol to the NPT to give the UN's nuclear inspectors the power to make unannounced checks of its atomic facilities.
Iran's ambassador to the IAEA, Ali Akbar Salehi, said a decision by Tehran to sign the protocol depended "upon the outcome of the board," apparently referring to the resolution not being too strong.
Meanwhile, Russia's atomic energy minister Alexander Rumyantsev said in Moscow Monday that Russia and Iran are likely to soon resolve differences over a key agreement that would launch the Islamic state's first nuclear reactor.
But close observers of the negotiations on Iran's controversial Bushehr power plant said Russia was becoming genuinely concerned over Iran's apparent demands to keep spent nuclear fuel for two years before returning it to Russia.
Western nations worry the fuel can be reprocessed to make nuclear bombs -- although most analysts agree Tehran still lacks the technology to attack another nation with such a weapon if it was ever developed.
Iran insisted Monday that it has fully cooperated with the IAEA and gave another stiff denial that it intends to acquire a nuclear arsenal.