Tehran is ready to allow nuclear inspectors access to its Marivan military site, an Iranian official said Saturday, according to AFP.
Marivan is a facility long suspected of being used to develop explosive weapons.
The declaration comes as Iran and six world powers hold talks in Vienna to reach a lasting agreement on Tehran's disputed nuclear program before Monday.
The Marivan site, close to the Iraqi border, was mentioned in a 2011 report by the International Atomic Energy Agency (IAEA) on Iran's alleged pursuit of nuclear weapons.
The UN agency suggested at the time that "large scale high explosive experiments" may have been carried out at the complex.
Britain, China, France, Russia, the United States and Germany have been locked in talks with Iran since February after an interim accord gave it some relief from economic sanctions in return for nuclear curbs.
"We are ready to allow the IAEA controlled access to the Marivan site," Behrouz Kamalvandi, spokesman for Iran's Atomic Energy Organization, was quoted as saying by the IRNA news agency.
He said the IAEA's view of Marivan was based on "false" information.
IAEA spokesman Gill Tudor said the watchdog "will discuss the offer" with Tehran.
"The situation regarding a visit to the Marivan region is not as simple as that conveyed by Iran," she told AFP.
As well as Marivan, IAEA inspectors are also interested in the Parchin military base, where they suspect tests that could be applied to a potential nuclear site have been carried out.
Iran has so far denied access to Parchin.
The Islamic Republic hotly denies its nuclear program is meant to build a nuclear weapon, even though the IAEA has revealed Iran is not abiding by the interim conditions in refusing to answer questions on the military aspects of its program.
Likewise, a former head of the IAEA revealed this month that Iran may have five times more advanced uranium centrifuges than previously thought, making the danger that Iran would be able to quickly develop a nuclear weapon all the more pressing.
Iranian officials in the past have called the question of Iran's uranium centrifuges a "trivial issue" that shouldn't stop talks.