Iran Admits Nuclear Facility Is Underground

An Iranian official confirmed Monday a uranium enrichment plant in central Iran is underground as a protection against airstrikes, but insisted that is not a sign the program aims to produce nuclear weapons.

U.S. officials have said building nuclear facilities underground is inconsistent with Iran's contention its atomic program is intended only for the generation of electricity. The Iranians deny Washington's accusation that they are trying to build nuclear weapons.

Ali Akbar Salehi, a nuclear affairs adviser to the foreign minister, said U.S. and Israeli threats forced Iran to take precautions to protect its technology, including the string of centrifuges used to enrich uranium — a process that can produce fuel for nuclear reactors that generate electricity but also make material suitable for atomic warheads.

"To protect the safety of equipment against possible danger of aerial attack, a major part of the plant has been constructed underground, especially where thousands of centrifuges need to be located," Salehi told The Associated Press.

It was the first public confirmation by Iran that the Natanz facility is underground.

On Saturday, Iran's top nuclear negotiator, Hasan Rowhani, confirmed Iran is building a tunnel next to another nuclear facility in Isfahan. He said that the tunnel, under a mountain, will be used to store unspecified equipment and that air attacks would not be able to destroy it.

The central cities of Natanz and Isfahan house the heart of Iran's nuclear program. The conversion facility in Isfahan reprocesses uranium ore concentrate, known as yellowcake, into uranium hexaflouride gas (search). The gas is then taken to Natanz and fed into the centrifuges for enrichment.

The facility at Natanz is at the foot of a mountain in an otherwise barren desert some 200 miles south of the capital, Tehran. Some of its buildings, which are believed to be administrative offices, are visible from the main road running from Kashan to Natanz.

There are military bases not far from the facility. Travelers who stop on the road close to the facility are approached by security officers in plainclothes and asked to leave.

Iran began its nuclear program in secrecy, and now says it has achieved proficiency in the full range of activities involved in enriching uranium.

Iran's former president, Hashemi Rafsanjani, said Sunday that Iran initially developed the program in secret and bought nuclear materials on the black market because of U.S. sanctions and European restrictions that denied Iran access to advanced civilian nuclear technology.

He said that Iran has been very open about the program since 2002, when secret aspects of its nuclear activities were revealed, and that it is cooperating with the International Atomic Energy Agency (search), the U.N. nuclear watchdog.

The government argues it is entitled to work on civilian uses of uranium enrichment under the Nuclear Nonproliferation Treaty (search).

Iran suspended enrichment-related activities last year to create confidence during negotiations over its program and avoid the U.N. Security Council considering sanctions. But it says maintaining the voluntary freeze depends on progress in talks with Britain, Germany and France, which are negotiating on behalf of the European Union.