Iranian state television has quoted the head of the United Nations' nuclear watchdog, Yukiya Amano, and Iran's lead negotiator, Saeed Jalili, as saying that they had held "intensive" and "very useful" talks in Tehran.
Amano, who heads the International Atomic Energy Agency (IAEA), was in Tehran to persuade Iran to permit IAEA inspections
of Iranian sites suspected of involvement in atomic-weapons research.
His visit came ahead of a round of nuclear talks between Iran and six world powers in the Iraqi capital, Baghdad, on May 23.
Amano, quoted by state broadcaster IRIB, said the "progress" made during discussions on May 21 will have a "positive effect" on the Baghdad negotiations.
Jalili also said he and Amano had "very good talks."
IRIB said discussions focused on nuclear disarmament, halting proliferation, and the peaceful use of nuclear energy.
Based on reporting by AFP and Reuters