Iran and six world powers ended an expert-level meeting over Tehran's disputed nuclear activities on Thursday, but there was no immediate word on whether they had come any closer to an elusive breakthrough deal, Reuters reported.
The two-day meeting was meant to prepare for the next round of political negotiations on November 7-8, building on a diplomatic opening created by the election of Hassan Rouhani as new Iranian president.
Rouhani, a pragmatist and a former chief nuclear negotiator for Iran, took office in August promising to try to resolve the dispute after years of confrontation and secure an easing of sanctions that have damaged Iran's oil-dependent economy.
Western diplomats had said the talks at the U.N. complex in Vienna could help define the contours of any preliminary agreement on scaling back Iran's uranium enrichment in return for an easing of sanctions. But they cautioned before the meeting that there was no such deal yet.
Around 3 p.m. (1400 GMT), delegations of nuclear and sanctions experts were seen leaving the conference room where the discussions began on Wednesday afternoon. Participants declined to comment on the nature of the closed-door talks.
Michael Mann, spokesman for the European Union's foreign policy chief Catherine Ashton, said only that the Vienna talks had sought to "address various technical questions and contribute to preparations for the next round of talks in Geneva".
Iran rejects accusations it is covertly researching the means to produce nuclear weapons, saying it is refining uranium only for energy generation and use in medical treatment. Uranium can also be to fuel nuclear bombs if refined to a high level of fissile concentration.
The expert-level discussions were the latest in a series of meetings over the last month, as Iran and the powers step up diplomatic efforts to try to end the decade-old row that could otherwise plunge the Middle East into a new war.
At talks with the United States, Russia, China, France, Britain and Germany in Geneva on October 15-16, Iranian negotiators expressed readiness to address concerns over the program but left many details unanswered about specific concessions they may be willing to make, diplomats said.
The powers' priority demand is for Iran to stop 20 percent enrichment, ship out existing stockpiles of the material and cease operations at its Fordow uranium enrichment site, buried deep underground.
Iran has signaled it may be willing to discuss suspending this higher-level enrichment if the West lifts painful sanctions on its oil and banking industries, something Western governments do not want to do as a first step.
Diplomats had said they would seek specifics at the meeting of experts, and at next week's follow-up talks to be conducted by senior foreign ministry officials in Geneva, on how far Iran is willing to go to allay international concerns.