Iran says the controversial Parchin military site is not included in an agreement it has struck with the UN atomic watchdog.
"Visiting Parchin is not included in the seven steps," said Iran's Atomic Energy Organisation spokesman Behrouz Kamalvandi on Sunday.
His remarks, reported by the ISNA news agency, came after two days of talks in Tehran with experts from the International Atomic Energy Agency (IAEA), building on a roadmap deal agreed in November.
The new deal requires Tehran to implement seven steps by May 15, including visits to a uranium mine and yellowcake factory in central Iran.
The IAEA suspects explosive tests took place in Parchin, a military site near Tehran, that are "strong indicators of possible nuclear weapon development".
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It has asked in vain for years to visit the facility, pointing to new information it has uncovered since its last visits to the site in 2005.
Six world powers negotiating with Iran on its current nuclear activities also called on Tehran in March 2012 to allow IAEA inspectors to visit the site.
Iran says it has no obligation to do so, as Parchin is a designated military site.
