Turkey says Iran is close to agreeing to a nuclear fuel swap deal aimed at easing Western concerns over Tehran's nuclear program.
Turkish Foreign Minister Ahmet Davutoglu spoke in Tehran amid Turkish and Brazilian mediation efforts.
Turkey's foreign ministry said a formal announcement could come as soon as later today.
Turkey and Brazil are non-permanent members of the UN Security Council, and have spoken out against imposing more UN sanctions against Iran for failing to halt its uranium enrichment program.
Iran had rejected a UN-backed plan to send low enriched uranium abroad for higher grade fuel for a research reactor because Tehran wanted the swap to take place on its soil.
Turkish Prime Minister Tayyip Erdogan -- in Tehran for the talks along with Brazilian President Luiz Inacio Lula da Silva -- said the swap could take place in Turkey.
After talks with Iranian leaders including President Mahmud Ahmadinejad, Lula said "the level of hope has increased."
Both Russia and the United States have expressed doubts the latest diplomatic efforts led by Brazil will succeed.
Washington is trying to build a consensus within the Security Council for a fourth round of UN sanctions against Iran.
Iran denies Western charges it is secretly developing a nuclear weapons program.
compiled from agency reports