The United Nations' top nuclear inspector, Herman Nackaerts, says talks with Iran have ended with no agreement and no date set for new talks.
This was the 10th round of talks since the beginning of last year between Iran and the International Atomic Energy Agency. U.N. inspectors want access to Iranian nuclear facilities and documents.
The IAEA is concerned Iran may be building a nuclear weapon and wants to visit such places as the Parchin military site.
Iran says Parchin is a standard military facility and insists its nuclear program is peaceful.
Iran's top nuclear negotiator, Saeed Jalili, held separate talks in Istanbul Wednesday with EU foreign policy chief Catherine Ashton. Their talks are focused on the possibility of another round of negotiations between Iran and the five permanent members of the U.N. Security Council plus Germany.
Those nations are pushing for Iran to stop some of its uranium enrichment activity, while Iran demands they recognize its right to enrich uranium.
The U.N. Security Council has passed multiple rounds of sanctions against Iran related to its nuclear program. The United States and other Western nations have enacted their own sanctions, including those targeting Iran's key oil exports.
The U.S. Treasury Department Wednesday imposed sanctions on a trading company and an exchange house in the United Arab Emirates for dealing with a blacklisted Iranian bank. Treasury also announced it is banning gold sales to Iran starting July 1. The ban is part of the U.S. effort to weaken the Iranian currency and isolate Iran from the global financial system.