GENEVA — A deal to limit Iran's nuclear program appeared close to completion Friday as negotiators from six world powers and Tehran smoothed remaining conflicts and top diplomats began arriving to join the talks.
After a rocky day Thursday, negotiators appeared for now to have overcome their differences on Iran's entitlement to enrich uranium and on how to curb progress on a partially built nuclear research reactor that Western powers view as a particular threat.
U.S. Secretary of State John Kerry left late Friday for Geneva to help "narrow the differences and move closer to an agreement," the State Department said. Russian Foreign Minister Sergey Lavrov arrived from Moscow early Friday evening, making him the first of the six nations' ministers to show up for a possible signing ceremony that would end a decade of usually stalemated negotiations.
"Negotiations are moving on a positive track," said Majid Takht-Ravanchi, an Iranian deputy foreign minister.
A deal would be a first-stage agreement that would give Iran temporary relief from the crushing Western sanctions on its economy in exchange for temporary limits on its nuclear program. Many nations fear that Iran, despite its insistence that its program is for peaceful purposes only, is seeking nuclear weapons capability.
This deal would open the way for tough bargaining on a final, comprehensive agreement that would take six months or longer to be reached.
A preliminary agreement would be a major step and could reduce the threat of another war in the Middle East. But as soon as it is signed, it is likely to come under attack by Republican and Democratic lawmakers and U.S. allies such as Israel and Saudi Arabia, who fear that it will be too lenient.
This week's round of meetings was the third in five weeks. The last session, on Nov. 8-10, broke down under circumstances that are still disputed by U.S., French and Iranian officials.
Despite the progress on Friday, diplomats emphasized that the deal was not complete and that other barriers could still arise.
Iranian Foreign Minister Mohammad Javad Zarif met repeatedly with European Union foreign policy chief Catherine Ashton to negotiate wording on a deal. Then the Iranians and the six powers — the United States, Russia, China, France, Britain and Germany — called their capitals to get approval.