The director general of the U.N. nuclear watchdog, which is investigating whether Iran carried out work related to developing an atom bomb, visited a sensitive military site during a trip to the country, the agency said on Sunday.
The military site, called Parchin, has been at the centre of a debate over the level of access that the International Atomic Energy Agency (IAEA) will have in policing a deal reached in July between Iran and six world powers.
The IAEA is due to issue an assessment this year on "possible military dimensions" of Iran's nuclear programme under a roadmap agreement accompanying that deal. One open question is whether Iran carried out high-explosives testing at Parchin that could be related to making a nuclear warhead.