The United States took a surprising stance on Friday supporting Iranian claims that it was not building a new secret uranium enrichment facility, after an Iranian opposition group exposed satellite imagery on Thursday allegedly proving the existence of a secret nuclear site some 120 kilometers from Tehran.
The Iranian dissident group said on Thursday the information came from a network of sources inside Iran affiliated with the exiled opposition group the National Council of Resistance of Iran (NCRI) and the People's Mujahideen Organization of Iran (PMOI).
Washington, which along with its European allies accuses Iran of trying to build nuclear bombs, said it had known about the facility for years and had no reason to believe it was nuclear.
"We have informed the International Atomic Energy Agency about all of our nuclear facilities, Iran's top nuclear official Ali Akbar Salehi said.
The NCRI in 2002 exposed Iran's uranium enrichment facility at Natanz and a heavy-water facility at Arak. But analysts believe the group, which opposes Iran's clerical establishment, has a mixed track record and a clear political agenda.
The group had satellite photographs of the alleged newly discovered site, which it said was under a mountain near Qazvin, about 75 miles (120 km) west of Tehran, and was about 85 percent complete.
Uranium enrichment can produce fuel for nuclear power plants or, taken to a higher level, for atomic bombs. Tehran says its nuclear program is aimed at generating power.
However, Iran's record of secrecy has stoked suspicions, heightened by the February launch of higher-grade uranium enrichment of 20 percent fissile purity, bringing it closer to weapons-grade material.
In Vienna, Britain's envoy to the United Nations nuclear watchdog on Friday called Iran "uniquely obstructive" for rejecting some inspectors from the IAEA.
Ambassador Simon Smith also suggested his government would look into claims by the dissident group that it had evidence of a new secret underground nuclear site.
Iran said in November that it had plans to build 10 more nuclear sites.