During the first session of the two-day talks, the sides reaffirmed the positions they set out at the previous meeting in Geneva in December, the agency said.

EU foreign policy chief Catherine Ashton is representing the G5+1 (Russia, China, the United States, France, Britain and Germany) and the Iranian delegation is represented by Saeed Jalili, the country's top nuclear negotiator.

On Thursday, Russian Foreign Minister Sergei Lavrov called for the talks to be all-encompassing, covering not only Iran's nuclear program but also "the prospect of dropping [the latest set of] sanctions as Iran begins to cooperate with the IAEA more effectively."

During the talks Iran expressed its readiness to realize a trilateral agreement reached in May 2010 between Iran, Brazil and Turkey that set out terms under which Iran would exchange in Turkey most of its 3.5 percent-enriched uranium for 20 percent-enriched fuel for use in a scientific research reactor in Tehran, local media said earlier on Friday.

That proposal was last year rejected by the Iran Six. The major world powers have been trying since 2003 to convince Iran to halt its uranium enrichment program and to alleviate concerns about its nuclear ambitions.

The West suspects Tehran of pursuing a secret nuclear weapons program, which Iran strongly denies, insisting it needs atomic energy solely for civilian purposes. Iran is currently under four sets of UN sanctions over its refusal to suspend uranium enrichment.