US Secretary of State John Kerry has said Iran backed out of a deal on its nuclear programme during talks with world powers in Geneva on Saturday.
Amid reports that France’s reservations scuppered an agreement, Mr Kerry told reporters in Abu Dhabi: “The French signed off on it; we signed off on it.”
Iran had been unable to accept the deal “at that particular moment”, he added.
Mr Kerry said he hoped in the next few months they could “find an agreement that meets everyone’s standards”.
Representatives from Iran and the so-called P5+1 – the US, UK, France, Russia and China plus Germany – will meet again on 20 November.
Iran stresses that its nuclear programme is for peaceful purposes only, but world powers suspect it is seeking to develop nuclear weapons.
In a separate development on Monday, the head of the International Atomic Energy Agency (IAEA), Yukiya Amano, said the agency had agreed a “roadmap for co-operation” with Iran to help resolve remaining issues.
Six specific access or information issues will be addressed over the next three months, offering a clear test of Iran’s willingness to provide greater clarity about its activities, says the BBC’s diplomatic correspondent Jonathan Marcus.
Progress between Iran and the IAEA is seen by experts as a vital parallel track to the talks between Iran and the major powers, he says.
Mr Amano said the deal was “an important step”. It opens the way for inspectors to visit a heavy-water plant being built in Arak and the Gachin uranium mine in Bandar Abbas, and for measures requested by the UN watchdog to be implemented.
Tehran says the reactor in Arak is intended for the production of radioisotopes for medical purposes, but its spent fuel will contain plutonium suitable for use in nuclear weapons.
Some reports said the latest talks failed because France had wanted to place tight restrictions on the facility in Arak.
However, US diplomats said the Iranian government’s insistence on formal recognition of its “right” to enrich uranium had been the major obstacle.
The Jerusalem Post quoted a senior US official as saying the P5+1 had approved a working document, but that it had been “too tough” for the Iranians.
Speaking at a news conference with UAE Foreign Minister Sheikh Abdullah bin Zayed Al Nahyan on Monday, Mr Kerry said: “The P5+1 was unified on Saturday when we presented our proposal to the Iranians.
“The French signed off on it, we signed off on it, and everybody agreed it was a fair proposal.
“Iran couldn’t take it at that particular moment; they weren’t able to accept.”
Mr Kerry also said that Israeli Prime Minister Benjamin Netanyahu’s public dismissal of the offer as a “bad deal” for the world had been premature.
“We are confident that what we are doing can actually protect Israel more effectively and provide greater security,” he added.
Mr Kerry’s comments on the prospects of an interim accord were echoed by French Foreign Minister Laurent Fabius, who told Europe 1 radio: “We are not far from an agreement with the Iranians, but we are not there yet.”
The heavy-water reactor and plant at Arak could be operational next year
Responding to the reports that Paris was behind the failure of the talks, he said: “France is neither isolated nor a country that follows the herd. It is independent and works for peace.”
Mr Fabius revealed that there had been several issues that “still need to be discussed with the Iranians”, including the facility in Arak, which could be operational by the end of 2014.
“We have to make arrangements for this reactor in Arak not to be activated as planned, for it not to lead to an atomic bomb,” Mr Fabius said.
Questions also remain over Iran’s stockpile of uranium enriched to a medium level of purity, or 20%. Experts say it could be enriched to 90%, the level required for a nuclear bomb, in a relatively short time.
“This stock at 20% must be dismantled and come back to 5%. The Iranian side still needs to make an effort [on this],” Mr Fabius explained.
But he also warned that the failure to agree a deal with Iran “would be a considerable problem in a few months”.