As Chinese and Russian foreign ministers joined Western officials in Geneva yesterday, France warned of serious stumbling blocks to a long-sought accord with Iran.
With unity among Western powers appearing to fray in talks on getting Tehran to curtail its nuclear programme, Iranian media quoted the Islamic Republic's deputy foreign minister, Abbas Araqchi, as saying "the issues are serious and there is still a gap in stances".
Iranian Foreign Minister Mohammad Javad Zarif said that if no deal was reached yesterday, talks could continue in a week to 10 days.
Iran's refusal to suspend work on a plutonium-producing reactor and downgrade its stockpile of higher-enriched uranium was standing in the way of an interim agreement to curb Tehran's nuclear programme in return for easing of sanctions, France's foreign minister said.
A Western diplomat in Geneva for the talks said the French were holding out for conditions on the Iranians tougher than those agreed to by the US and France's other negotiating partners.
Laurent Fabius' remarks to France-Inter radio were the first to provide some specifics on the obstacles at the talks, which entered a third - unscheduled - day.
He spoke by telephone from Geneva, where he, US Secretary of State John Kerry, Russian Foreign Minister Sergey Lavrov and counterparts from Britain and Germany negotiating with Iran, consulted on how to resolve the obstacles at the talks.
Foreign Minister Wang Yi was also expected to attend the talks, Chinese state radio said yesterday.
Fabius mentioned differences over Iran's Arak reactor southeast of Tehran, which could produce enough plutonium for several nuclear weapons a year once it goes online.
He also said there was disagreement over efforts to limit Iran's uranium enrichment to levels that would require substantial further enriching before they could be used as the fissile core of a nuclear weapon.
"As I speak to you, I cannot say there is any certainty that we can conclude," Fabius said, stressing that Paris could not accept a "sucker's deal".
His pointed remarks hinted at a rift brewing within the Western camp.
The six powers are considering a gradual rollback of sanctions that have crippled Iran's economy. In exchange, they demand initial curbs on Iran's nuclear programme, including a cap on uranium enrichment to a level that cannot be turned quickly to weapons use.
Iran, which denies any interest in such weapons, currently runs more than 10,000 centrifuges that have created tonnes of fuel-grade material that can be further enriched to arm nuclear warheads.
It also has nearly 200kg of higher-enriched uranium in a form that can be turned into weapons much more quickly. Experts say 250kg of that 20 per cent-enriched uranium is needed to produce a warhead.
Iran says it expects Arak, the plutonium-producing reactor, to be completed and go online some time next year. It would need additional facilities to reprocess the plutonium into weapons-grade material and the United Nations' nuclear agency monitoring Iran's atomic activities says it has seen no evidence of such a project.
As well as suspending work on Arak, Iran is being asked to blend down "a great part of this stock at 20 per cent to 5 per cent", Fabius said. Uranium enriched to 5 per cent is considered reactor-fuel grade and upgrading it to weapons-level takes much longer than for 20 per cent-enriched uranium.
He also suggested the six powers were looking for an Iranian commitment to cap future enrichment at 5 per cent.
Associated Press, Reuters