Inspectors from the UN nuclear watchdog IAEA, or the International Atomic Energy Agency, on Monday visited a sensitive Iranian heavy water nuclear reactor in Arak, the official IRNA news agency reported.
The IAEA inspectors "took five hours to inspect the 40-megawattreactor," said IRNA, quoted an unnamed Iranian official. The report didn't disclose more details over the inspection.
The inspection came following a recent agreement reached between Iran and the IAEA to resolve the remaining issues on Iran's nuclear program, the official added.
IAEA's deputy chief Olli Heinonen and a senior Iranian envoy have recently agreed to this inspection to Arak nuclear reactor when Heinonen's delegation visited Iran on July 11.
Iran has blocked inspections from the IAEA to its nuclear sites since January this year after the UN Security Council imposed sanctions over the country's controversial nuclear program.
The Arak reactor, located about 280 km southwest of Iran's capital, could produce plutonium as a by-product when it is completed in 2009. Yet plutonium can also be used to make nuclear bombs.
The U.S. and other Western countries have accused Iran of trying to develop atomic weapons under a civilian cover, but Iran denies such accusation, saying it just wants to generate electricity.