Head of Atomic Energy Organization of Iran (AEOI) Ali-Akbar Salehi said the agreement reached in Geneva between Iran and the powers is a "great success" for Iran, official IRNA news agency reported on Sunday.The agreement could be regarded as an end to the long-standing dispute over the country's nuclear issue, Salehi was quoted as saying. He congratulated Iran's Supreme Leader Ayatollah Ali Khamenei and the Iranian nation on the deal describing the talks as " fruitful," according to the report. After intensive negotiations, the P5+1 group -- the five UN Security Council permanent members Britain, China, France, Russia and the United States plus Germany -- and Iran have reached a first-step agreement on Iran's nuclear program, EU foreign policy chief Catherine Ashton announced early Sunday morning. Ashton, who represents the P5+1 group, during the talks with Iran made the announcement at the Palace of Nations, the headquarters of United Nations Office in Geneva.