GENEVA — U.S. Secretary of State John Kerry and world's other top diplomats joined Iran nuclear talks Saturday, cautioning there were no guarantees their participation would be enough to seal a deal to curb Tehran's atomic program in return for limited sanctions relief.
The goal is a six-month agreement to freeze Iran's nuclear program while offering Iran incentives through limited sanctions relief. If the interim deal holds, the parties would negotiate final stage deals to ensure Iran does not build nuclear weapons.
Britain's Foreign Secretary William Hague spoke of "very difficult negotiations, saying "narrow gaps" remain on the same issues that blocked agreement at the last round earlier this month.
"We're not here because things are necessarily finished," Hague told reporters. "We're here because they're difficult, and they remain difficult."
Kerry and his counterparts from Russia, Britain, France, China and Germany headed for Geneva after diplomats said Friday that Iranian Foreign Minister Mohammad Javad Zarif and top European Union diplomat Catherine Ashton had made progress on a key sticking point — Iran's claim to a right to produce nuclear fuel through uranium enrichment.
Details were not released but it appeared the two sides were trying to reconcile Iran's insistence that it has a right to enrich for peaceful purposes while assuaging fears that Tehran was secretly trying to build a bomb, a charge the Iranians deny.
As the talks entered an intensive phase, Chinese Foreign Ministry spokesman Hong Lei said the negotiations had reached "the final moment," according to China's Xinhua news agency.
Others were less upbeat.
Germany's Foreign Minister Guido Westerwelle spoke of "a realistic chance" for a deal "but there is still a lot of work to do." Russian Deputy Foreign Minister Sergei Ryabkov told RIA-Novosti news agency that negotiations were very close to a breakthrough but "unfortunately I cannot say that there is assurance of achieving this breakthrough."
French Foreign Minister Laurent Fabius told reporters he wanted "a deal — but a solid deal — and I am here to work toward that end."
France's concern that the negotiators were rushing into a flawed deal with Iran helped delay an agreement during a session nearly two weeks ago.
Other obstacles include Iran's plutonium reactor under construction in Arak as well as a formula for providing limited sanctions relief without weakening international leverage against Iran.
Enrichment is a hot-button issue because it can be used both to make reactor fuel and to make nuclear weapons. Iran argues it is enriching only for power, and scientific and medical purposes, and says it has no interest in nuclear arms.
Washington and its allies point to Tehran's earlier efforts to hide enrichment and allege it worked on developing such weapons.
Iran has insisted on that right throughout almost a decade of mostly fruitless negotiations. But Zarif last weekend indicated that Iran is ready to sign a deal that does not expressly state that claim.
Iranian hard-liners are suspicious of talk of nuclear compromise since moderate President Hassan Rouhani took office in September, fearing his team will give not get enough in terms of sanctions relief over the six-months of any first-stage agreement.
Several U.S. senators — both Democrat and Republican — have voiced displeasure with the parameters of the potential agreement, arguing that the U.S. and its partners are offering too much for something short of a full freeze on uranium enrichment.
On Wednesday, Iran's supreme leader, Ayatollah Ali Khamenei, said his country would never compromise on "red lines." Since then Tehran has publicly reverted to its original stance — that the six powers must recognize uranium enrichment as Iran's right, despite strong opposition by Israel and within the U.S. Congress.
Still, comments from Iranian officials in Geneva indicated that reverting to tough talk on enrichment may be at least partially meant for home consumption.
In Geneva, a senior Iranian negotiator said the Iranian claim to the right to enrich did not need to be explicitly recognized in any initial deal, despite Khamenei's comment, adding that the supreme leader was not planning to intervene in the talks. He did suggest, however, that language on that point remained difficult and that there were other differences.
The negotiator demanded anonymity because he was not allowed to discuss the confidential talks.
Associated Press writers Deb Riechmann and George Jahn in Geneva, and Robert H. Reid in Berlin contributed to this report.