Iran agreed in principle today to export much of its stock of enriched uranium for processing and to open its newly revealed enrichment plant to UN inspections within a fortnight.
The agreements, struck at negotiations in Geneva with six major powers, represented the most significant progress in talks with Tehran in more than three years, and offered hope that the nuclear crisis could be defused, at least temporarily.
Western officials cautioned that the preliminary agreements could unravel in negotiations over the details. But if the deals are completed, it will push back the looming threat of further sanctions and possible military action.
A full day of talks in a lakeside villa just outside Geneva included the most senior and substantive bilateral meeting between an American and an Iranian official for three decades. At a lunchtime break in the proceedings, the US delegate, William Burns, took aside Iran's chief nuclear negotiator, Saeed Jalili, for a one-to-one chat that lasted 40 minutes.
At the end of the negotiations, the EU foreign policy chief, Javier Solana, on behalf of the six-nation group – known as the E3+3 and consisting of Britain, France, Germany, the US, Russia and China – said the meeting "represented the start of what we hope will be an intensive process".
The most concrete, and potentially most significant, gain from the Geneva talks was an agreement in principle that Iran would send a significant quantity of its stockpile of low-enriched uranium (LEU) for further enriching and processing in Russia and France respectively, so that it could be used as fuel in its research reactor in Tehran, which makes isotopes for medical uses. President Barack Obama said yesterday: "Taking the step of transferring its low-enriched uranium to a third country would be a step towards building confidence that Iran's programme is peaceful."
Western experts at today's session said that up to 1,200kg of LEU could be involved, three-quarters of Iran's declared stock. It would be further enriched in Russia from below 5% purity to just under 20% – enough for the research reactor, but not enough for a warhead.
Once it had been turned into fuel at a French plant it would be extremely hard to turn into a weapon, and so would defuse the immediate international tension surrounding the purpose of Iran's uranium stockpile, which some scientists say is enough to make a warhead.
The proposal has been put together over the past month between the US and Russia, and seeks to fulfil an Iranian need for reactor fuel in a way that reduces international tensions.
Solana said that the details of the deal would be hammered out at a meeting of experts from Iran, France and Russia at the headquarters of the International Atomic Energy Agency (IAEA) on 18 October.
On Saturday, the IAEA director, Mohamed ElBaradei, is due in Tehran to seal another of the deals struck in Geneva – on when inspectors from the UN agency can inspect a new enrichment plant under construction in Qom, the existence of which only became known last week. Solana said that he hoped the inspection would take place "within the next couple of weeks".
The third agreement struck in Geneva is for the six-nation group to meet Iranian officials again before the end of this month to negotiate a long-standing offer to Iran of a "freeze-for-freeze".
Under that proposal, first put forward last year, the international community would impose no new sanctions, and Iran would not expand or accelerate its uranium enrichment programme.
NEW ADDA senior US official in Geneva said yesterday that until uranium enrichment was suspended "the overall problem of Iran's nuclear programme remains".
The Iranians were assured yesterday that a freeze on sanctions would include all multilateral and bilateral measures, and that the Obama administration – unlike its predecessor – would remain a full participant in the negotiations throughout.
The deadline for further progress on all these fronts is still December, as stipulated earlier this year by Obama.
Yesterday, the US president said: "We're not interested in talking for the sake of talking. If Iran does not take steps in the near future to live up to its obligations, then the United States will not continue to negotiate indefinitely, and we are prepared to move towards increased pressure."
Speaking in Washington after the talks ended, the US secretary of state, Hillary Clinton, said it had been a productive day, but added a note of caution. "I will count it as a positive sign when it [Iran] moves from gestures and engagements to actions and results," she said.