“Any kind of suspension or freeze (of uranium enrichment) is out of the question,” said the official before the start of the one-day meeting aimed at sounding out Iran’s readiness to negotiate an end to the dispute over its nuclear work.

The high-level US participation in the one-day meeting in Geneva, together with Iranian comments playing down the likelihood of an attack by the US and Israel, had raised hopes of progress and helped ease record oil prices.

But the optimism was tempered by US insistence that despite the presence of its envoy William Burns, real negotiations cannot begin until Iran has frozen sensitive nuclear work, a step Tehran has repeatedly ruled out.

“That remains the US position and it will continue to be the US position,” the US Secretary of State Condoleezza Rice told a news conference in Washington.

Speaking in Tehran ahead of the talks, Iranian Foreign Minister Manouchehr Mottaki welcomed the meeting: “We evaluate today’s Geneva negotiations as positive and constructive.” “Saturday’s meeting might continue with several others so that the view points of all sides can be put on the table so that we reach ... agreement,” he told reporters.