Iran backed down in the face of fierce international pressure today and dropped a demand for changes to a key agreement designed to reassure the world that Tehran does not want nuclear weapons, Western diplomats said.
But they cautioned the tentative deal between Britain, France, Germany and Iran could still collapse as Tehran had yet to give its final approval to the agreement which was still being finalised.
A spokeswoman for the UN nuclear watchdog said the agency's meeting had adjourned until Monday to allow time for the parties to clarify their positions.
A diplomat close to the talks said more work remained to be done by Iran. Asked how soon that might happen, the diplomat said: "Not for some days yet. They are famous for coming out with different things at the last minute."
Last week, Iran promised the European Union it would halt all activities related to uranium enrichment, a process that creates atomic fuel for power plants or weapons, in a bid to neutralise the threat of economic sanctions.
The ink on the hard-won accord was barely dry, however, when Tehran demanded an exemption for some 20 enrichment centrifuges for research purposes. Western diplomats said this was impossible and could only deepen suspicions that Tehran has a secret weapons programme, as Washington alleges.
"They (Iran) have agreed to drop the demand and (the EU) are awaiting confirmation that a letter has been given to (UN nuclear watchdog chief Dr Mohamed ElBaradei) confirming this," the diplomat told Reuters. Other diplomats confirmed the deal.
But the head of the Iranian delegation to this week's International Atomic Energy Agency (IAEA) board of governors meeting, Mr Hossein Mousavian, said there was no final agreement and that Iran had not sent any letter to Dr ElBaradei yet.
"Either until late tonight or tomorrow we'll have the final Tehran response," he told reporters.
US President George W. Bush praised the efforts of the EU's "Big Three", but said that any deal reached with Tehran would have to be verifiable.
Asked what broke the three-day deadlock over Iran's request, which had threatened to wreck the agreement, one diplomat said: "It was (the EU's) hard stance. The Iranians just gave up."