WASHINGTON: US Secretary of State Hillary Clinton and Defense Secretary Robert Gates described last week's nuclear talks with Iran as a positive step but said it was too early to predict the outcome of the negotiations.

Clinton said the session in Geneva "was a worthwhile meeting," as the Iranians had agreed to inspections of all nuclear sites, to ship low-enriched uranium abroad for processing and to another round of talks later this month.

"But as the president has said and I and others have also made clear, this is not by any means a stopping point. There is much more to be done. We expect much more," Clinton told CNN in a joint interview with Gates.

She added that "on balance, what came out of the meeting in Geneva was positive."

Asked if the Iranians were committed to resolving the dispute over their nuclear program, Clinton said: "We don't know yet. We don't know."

Gates said he agreed. "I think the jury's out."

The defense secretary said deadlines and requirements had to be strict and detailed enough "that we have some indication of whether they're serious or not."

Iran tentatively agreed in Geneva to ship some of its stocks of low enriched uranium abroad for processing into fuel for an internationally supervised research reactor in Tehran.

Clinton, in an interview taped before an audience at George Washington University, said a team of technical experts would meet later this month "to see how to put into action what we certainly believed was an agreement in principle."

She added: "nothing is finished until it's finished."

Clinton said the progress at the Geneva talks had bought time to assess Iran's actions and that while engaging with Tehran, the administration was working with other world powers to prepare punitive sanctions in case negotiations failed.

Iran is to meet again with Britain, China, France, Germany, Russia and the United States on October 19 for more discussions on Tehran's nuclear work after last week's talks, the first in 15 months.

Gates said he had long believed that Iran wanted to develop nuclear weapons but said it was unclear whether Tehran had "begun a weaponization program."

Both cabinet secretaries said that the US approach was designed to convey to Iran that pursuing a nuclear arsenal would undermine its security and damage its own economic and national interests.

Gates warned that Iran could set off a dangerous nuclear arms race across the Middle East that would ultimately pose a greater threat to its security. "Is that in their interests?"

Mohamed ElBaradei, the head of the International Atomic Energy Agency (IAEA), flew in to the Iranian capital on Saturday to work out procedures for UN inspections of Iran's newly disclosed uranium enrichment plant near the holy city of Qom.

Tehran's disclosure before last week's Geneva talks that it was constructing a second nuclear enrichment plant inside a mountain at Qom triggered worldwide outrage.

Iran insists its nuclear program is designed for purely peaceful purposes, while the United States accuses Tehran of a clandestine effort to build nuclear weapons.