The United States, Britain and France will brief the United Nations Security Council today on their proposed resolution that would give Iran another chance to curb its nuclear programme.
But the Western allies probably will not distribute a text that Russia and China are opposed to. Moscow and Beijing fear it would be a step towards sanctions or even military action, although the draft will not threaten either measure.
"We will be explaining to the full council at that point where our thoughts are and what direction they will take," US Ambassador John Bolton told reporters.
He said it would be "helpful to apply greater pressure on Iran" so that all 15 members of the council, not just the Western powers, could give their views.
The plan is to introduce shortly a resolution under Chapter 7 of the UN Charter, making legally binding a March council statement that asked Iran to suspend uranium enrichment work - a process that could be used for electricity generation or making an atomic weapon.
There would be a deadline for Iran to comply but the measure would not threaten any action. Chapter 7 allows for sanctions or even military action but a separate resolution is necessary to specify either step.
No vote has been scheduled. The text also will be under discussion at a meeting on Monday and Tuesday among the foreign ministers of Germany and the five permanent council members - the United States, Britain, France, Russia and China.
Iran maintains its nuclear programme is legal and that it does not seek a bomb. It has accelerated uranium enrichment but is still far below the level needed to make an atomic bomb.