Iran has formally announced that it has ordered an immediate halt to spot checks by the UN of its nuclear sites and its suspension of uranium enrichment after having its nuclear program reported to the UN Security Council.
The Iranian President, Mahmoud Ahmadinejad, had earlier said his country's enemies needed Iran more than Iran needed them.
He siad that such pressure would do nothing to stop his government from developing nuclear power for electricity.
The decision to refer Iran to the Security Council was taken by the UN nuclear watchdog, the International Atomic Energy Agency, at a session in Vienna yesterday.
The US President, George W Bush, has said the decision to refer Iran's nuclear programme has sent a clear message to the government in Tehran that it could not acquire nuclear weapons.
In a statement, Mr Bush signalled, however, that a period of intense diplomatic effort would now begin to resolve the crisis.
Meanwhile, Iran has been holding talks with Russia about a plan to enrich uranium outside Iran.
The future of these talks is, however, in some doubt now that the matter - with Russia's agreement - is being referred to the UN.
Speaking in Munich, where he is attending a security conference, Russia's Deputy Prime Minister, Sergei Ivanov, has said he is not sure that sanctions would be effective.
