Six major powers meet today over a European draft UN resolution banning Iranian trade on nuclear materials and ballistic missiles that has drawn criticism from the United States.
France, Britain and Germany sent Russia and China the text on Tuesday of a Security Council sanctions resolution that would require nations to stop the supply, sale or transfer of materials for Iran's nuclear and ballistic missile programs and freeze any financing for them.
But, among other US objections, the measure exempts Russia and allows it to continue construction of a nuclear power plant for Iran at Bushehr, diplomats said.
The Bush administration wants to make sure Moscow does not deliver a fuel cycle that could be used for weapons.
Today all six countries hold an initial meeting on the resolution, which Russia and China had sent to their governments for analysis.
More changes are expected to the European draft before it is circulated to the full 15-member Security Council.
A unified front among Britain, France, Germany - lead negotiators with Iran - and the United States has been key to efforts to curb Tehran's nuclear programme, which the West says is aimed at making weapons but Iran maintains is for energy production.
The Bushehr plant in southwestern Iran is to begin operations next year.