The US and the European Union believe Friday’s report by Mohamed El Baradei, head of the International Atomic Energy Agency, will set the stage for a UN Security Council resolution, since there is little chance that Tehran will meet the council’s demand for “full and sustained suspension” of uranium enrichment, which can produce weapons-grade material.

But on Thursday Vladimir Putin, Russia’s president, warned against too great an intervention by the Security Council – a path Moscow feels could lead to confrontation.

“We think that the IAEA must continue to play a key role and it must not shrug off its responsibilities to resolve such questions and shift them on to the UN Security Council,” he said at a summit with Angela Merkel, German chancellor.

European officials argue that, far from sidelining the IAEA, any action by the council would seek to bolster its authority.

The Chinese government also called for restraint. Moscow and Beijing, which have growing energy and economic links with Iran, fear that a UN resolution might be used to justify military action at a later stage.

The US has stepped up efforts to assuage such concerns. “Forcible change of the Iranian regime is not the objective of American policy,” Philip Zelikow, a top adviser to US secretary of state Condoleezza Rice, told the Financial Times.

“Right now, we haven’t completed implementing a diplomatic strategy. That diplomatic strategy involves underscoring to the Iranian regime the costs of its behaviour.”

US and EU diplomats hope to win Security Council backing for a resolution on Iran by mid-June. Such a resolution would not involve sanctions but would probably set out a new deadline for Iran to halt nuclear enrichment.

Mr ElBaradei has been pushing Iran for a “technical break” in uranium enrichment to allow negotiations over the nuclear programme to resume.