Iran threatened yesterday to halt snap UN inspections of its nuclear facilities if it is taken to the UN Security Council, and Britain said the council would consider sanctions if Tehran defied international demands.
The US and the EU's three biggest powers said on Thursday that nuclear talks with Iran were at a dead end and Tehran should be brought before the Council.
Iranian Foreign Minister Manouchehr Mottaki said such a step would have "consequences" for the West.
"The government will be obliged to end all of its voluntary measures if sent to the UN council," state news agency IRNA quoted him as saying.
Iran has repeatedly threatened to end snap checks and resume uranium enrichment if it is reported to the Security Council.
The Iranian parliament enacted legislation in November that obliges the government to respond in this way, bringing it closer towards a collision course with the UN.
Cooperating with snap UN inspections is voluntary on Iran's part and halting them would not violate its international treaty obligations. However, it would reduce Iran's cooperation with the UN nuclear watchdog to the legal minimum.
Accusing Iran of turning its back on the international community, the EU's big three -- Britain, Germany and France -- said it had consistently breached its commitments and failed to show the world its nuclear activities were peaceful.
"Obviously if Iran failed to comply, the Security Council would then consider sanctions," British Foreign Secretary Jack Straw told BBC Radio after the EU3 called for an emergency meeting of the International Atomic Energy Agency (IAEA).
Asked if force were an option, he said: "No one is talking about invading Iran or taking military action against Iran".
Asked if there should be sanctions, Straw said: "That will be on the table but there are prior stages here. Our approach is firm but it has also got to be a sensible patient approach which ensures that there is a continuation of the very substantial international consensus which we have built up."
Straw said he had a "strong suspicion" that Iran wanted to build a nuclear bomb but stressed that there was no categorical evidence to prove that.
Concern over the Iran crisis is spreading steadily through global financial markets, with equity investors beginning to price in the geopolitical risks that have lent support to oil and gold prices through the week and lifted the safe haven Swiss franc by about one percent versus the US dollar.
Oil held above US$64 a barrel yesterday, supported in part by supply concerns about Iran, with investors worried that Security Council involvement could keep the market on edge for months.
The IAEA's board is expected to meet early next month to consider referring Iran to the Security Council.
In the past Russia and China have opposed this, but European diplomats said they were unlikely to vote against it after Iran ignored a plea made by all the council's five permanent members at the weekend not to proceed with uranium enrichment.
Asked if US Secretary of State Condoleezza Rice had won a pledge from the Russians not to block referral, one European diplomat said: "I believe that is the case."
"Whether or not Rice has got that promise, I think it's politically impossible for the Russians to block a transfer [of the Iranian nuclear dossier] from the IAEA to the Security Council. Whether, when it comes to the resolution, they will vote in favour or abstain doesn't really matter," he added.