AP, Lausanne :The United States and Iran have moved close to agreement on key aspects of a nuclear deal but some problems remain four days ahead of a target date for an initial agreement, officials said Sunday.Two officials told The Associated Press that Iran has tentatively accepted limits on machines it could use to enrich uranium to 6,000 – or even less – at its main site.Diplomats are in Switzerland for talks ahead of a March 31 target for the outline of a final deal to be negotiated by the end of June.The officials say Iran has agreed to ship out all enriched uranium it produces to Russia. Enriched uranium can be used to make the fissile core of a nuclear weapon.They say problems remain on the length of any restrictions on Iran’s nuclear program, monitoring Tehran’s compliance and other issues.The officials demanded anonymity because they are not authorized to discuss the confidential talks.U.S. Secretary of State John Kerry cancelled plans to return to the United States for an event honoring his late Senate colleague Edward Kennedy in order to remain at the ongoing talks in Switzerland.On Saturday officials expressed guarded optimism that after 18 months of tortuous negotiations and two missed deadlines a breakthrough might be in sight for a deal ending 12 years of tensions.”We’re moving forward,” Iranian Foreign Minister Mohammad Javad Zarif, hunkered down with US Secretary of State John Kerry in Switzerland since Thursday, told reporters.”I think we can in fact make the necessary progress to be able to resolve all the issues and start writing them down in a text,” Zarif said.German Foreign Minister Frank-Walter Steinmeier, who like French counterpart Laurent Fabius joined the negotiations on Saturday, said the talks were in the “endgame”. Steinmeier added however that “the final metres are the most difficult but also the decisive ones”.Russia’s chief negotiator, Sergei Ryabkov was quoted by the RIA Novosti news agency as saying the chances of a deal were “more than 50/50”.EU foreign policy chief Federica Mogherini, who arrived late Saturday, said negotiators “have never been so close to a deal” but added there remained “critical points” to resolve.Russian Foreign Minister Sergei Lavrov and China’s Wang Yi were reportedly due to join the talks on Sunday. Britain’s Philip Hammond was also expected, completing the line-up.
