GENEVA - A senior Iranian official ruled out any freeze in uranium enrichment on Saturday, rejecting a central demand of major powers at talks on its nuclear programme attended for the first time by a senior US official.
"Any kind of suspension or freeze (of uranium enrichment) is out of the question," the official said 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 United States 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," 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."
"Today'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.
Mottaki did not elaborate what he meant by agreement, but added that he hoped the Geneva talks would pave the way for agreeing on "a modality and a framework" for further negotiations.
His tone reflected that of Iran's chief nuclear negotiator Saeed Jalili, who spoke of his "positive intentions" as he arrived in Geneva on Friday for the talks with officials from the United States, Russia, China, France, Britain and Germany -- the so-called sextet.
Jalili shook hands with EU foreign policy chief Javier Solana as they went into the first session of talks, but neither man spoke to reporters. Burns also said nothing as he went in.
'Creative' Diplomacy
Jalili has a mandate from Iran's Supreme Leader Ayatollah Ali Khamenei and President Mahmoud Ahmadinejad to take any decision needed, a senior Iranian official told Reuters, adding that the meeting "will clarify the fate of the negotiations".
Iran's Fars news agency quoted Ahmadinejad as telling Russian President Dmitry Medvedev that he hoped the Geneva talks would help "resolve the existing issues".
Iran, the world's fourth-largest oil producer, rejects suspicions that it wants the atom bomb, saying the aim of the programme is to generate electricity so that it can export more crude oil and gas.
Western diplomats say they want the talks to clarify Iran's response to an enhanced sextet offer, delivered last month, of technical and commercial incentives to suspend uranium enrichment.
Asked about the Iranian official's rejection of suspension, Solana's spokeswoman Cristina Gallach said: "We have to wait to this afternoon to see the Iranian position. We are ready to look at creative manners to allow negotiations to start in full agreement with the UN Security Council."
The UN has imposed three sets of sanctions on Iran in a stand-off that goes back to the revelation in 2002 by an exiled opposition group of the existence of a uranium enrichment facility and heavy water plant in the country.
Tension has intensified since Tehran tested missiles last week, alarming Israel and unsettling energy markets on fears that conflict could disrupt supply.
Yet oil prices slipped on Friday, ending 13 percent down from last week's record of over $147 a barrel of crude.
Traders cited as factors the attendance of Burns -- a career diplomat who helped restore US ties with Libya in 2006 -- and a comment by Mottaki that the chances of an Israeli or US strike were "almost zero".