Iran has rejected allegations by a dissident group that it is building a secret uranium enrichment site.
The People’s Mujahideen of Iran (PMOI) says it has satellite images of the facility, 120km (75 miles) from Tehran.
But nuclear chief Ali Akbar Salehi insisted Iran had declared all of its activities to the International Atomic Energy Agency (IAEA).
US officials said they knew about the plant but did not believe it had a nuclear function.
The PMOI and allies from another exiled group, the National Council of Resistance of Iran, have revealed secret nuclear facilities in the past.
But they have also made exaggerated and mistaken allegations, and analysts say they have a clear political agenda.
The PMOI has released images it says show a tunnel facility under construction near Qazvin, and cites sources within Iran as confirming that the plant is a uranium-enrichment facility.
