PITTSBURGH — Western powers and Russia Friday turned up the heat on Iran to suspend its uranium enrichment program after the U.S., France and Britain revealed that the Islamic Republic has secretly been building an underground facility that could be used to produce nuclear weapons fuel.
"The size and configuration of this facility is inconsistent with a peaceful program," President Barack Obama said in a joint announcement with British Prime Minister Gordon Brown and French President Nicolas Sarkozy at the G-20 economic summit in Pittsburgh.
Unlike Brown and Sarkozy, Obama didn't explicitly threaten tougher economic sanctions if Iran continues to reject five U.N. resolutions that require it to suspend uranium enrichment and accept a deal to ensure that its program is for civilian purposes only.
However, he made it clear that he remains committed to previous threats to seek harsher measures.
"The Iranian government must now demonstrate through deeds its peaceful intentions or be held accountable to international standards and international law," Obama warned.
Asked if there's a growing possibility of the use of force, Obama told reporters Friday afternoon that he wasn't "taking any options off the table. But, he added: "I will also reemphasize that my preferred course of action is to resolve this in a diplomatic fashion. It's up to the Iranians to respond."
Sarkozy said that additional "sanctions will have to be taken" if "by December there isn't an in-depth change by the Iranian leaders." Accusing Iran of "serial deception," Brown said that Britain is prepared to "implement further and more stringent sanctions."
Obama, Brown and Sarkozy called on Iran to allow U.N. inspectors into the facility, a demand echoed by Russian President Dmitry Medvedev, who said in a statement that the site "violates decisions of the United Nations Security Council."
Despite his tough rhetoric, Medvedev said nothing about supporting tougher sanctions.
Responding to the announcement, Iranian President Mahmoud Ahmadinejad told reporters in New York that U.N. inspectors could visit the facility, but he insisted that it was legal under existing agreements with the U.N. International Atomic Energy Agency.
This is the second time since 2002 that Tehran has been caught hiding major nuclear facilities from international inspectors. Friday's disclosure intensified a seven-year dispute over its program and raised the stakes for Oct. 1 talks in Geneva, Switzerland among top diplomats from Iran, the U.S., Britain, France, Germany, China and Russia.
Enrichment can produce either low-enriched uranium for power reactors — which Iran has repeatedly asserted is the purpose of its program — or highly enriched uranium for nuclear weapons, which Western powers suspect Tehran of covertly developing with knowhow and technology originally bought from a Pakistani-run smuggling ring.
Iran has insisted for years that it's fully disclosed all its nuclear sites and activities to the IAEA, but its concealment of the new facility appeared to violate the prohibitions on new enrichment activities in the U.N. resolutions. Ahmadinejad insisted that Iran had given adequate notice of the facility to the IAEA, a contention the agency disputed, the U.S. and other powers.
The new facility is located in a tunnel complex buried in a mountain base of the elite Islamic Revolutionary Guards Corps, about 20 miles north of the holy city of Qom, U.S. intelligence officials said. The officials requested anonymity, as they weren't authorized to speak publicly.
It is designed to hold about 3,000 centrifuges, which is too few to produce regular supplies of low-enriched uranium fuel for its civilian nuclear reactor at Bushehr, these officials said, citing intelligence developed by the U.S., France and Britain. That number, however, is sufficient to produce one weapon's worth of highly enriched uranium a year once the facility begins full-scale operation.
Iran is constructing support buildings, and "intelligence indicates that earlier this year, they began installing infrastructure for centrifuges," said one U.S. intelligence official, who wasn't authorized to speak publicly and requested anonymity.
"We have been aware of it for a number of years," the official said. "There was dialogue with allies from a very early point, and as intelligence was shared, all became increasingly confident that the purpose of the facility was uranium enrichment."
"We have excellent access. We have multiple independent sources of information that allow us to corroborate the information and we are highly confident in the judgment," said the U.S. intelligence official, who declined to elaborate.
A senior Western official, who requested anonymity because of the matter's sensitivity, cautioned that U.S. technical experts "haven't reached any hard and fast conclusions. It could be any number of things . . . (but) it walks and quacks and looks like a facility that has . . . (the) probability of military applications."
The Kremlin said in a statement that Iran "must cooperate in this investigation" and "must provide proof of its commitment to a peaceful nuclear program by the October 1 meeting."
China has made ambiguous statements all week about whether it would support tougher sanctions, but it's unlikely to be the only country to oppose new measures if Russia goes along with them.
Experts say new measures could include having other countries adopt the financial sanctions the U.S. already has imposed on state-run Iranian banks. Some members of Congress called for a ban on exporting gasoline to Iran. Although it's the world's fourth-largest petroleum producer, Iran must import gasoline because it lacks refining capacity.
Some experts also argued that sanctions could be more effective in the wake of Iran's disputed June presidential election, which has sparked a widespread political movement opposed to Ahmadinejad.
There was no sign that the revelation of the new site or the talk of tougher sanctions would derail the talks, with all sides saying they wanted them held.
Ahmadinejad appeared to reaffirm Iran's stance that the nuclear issue won't be on the table. He told Time Magazine that it was "definitely a mistake" for Obama to have revealed the facility and that it "simply adds to the list of issues to which the United States owes the Iranian nation an apology over."
The U.S., France and Britain would "regret this announcement," Ahmadinejad later told a New York news conference.
The Vienna, Austria-based IAEA said that Iran informed it in a letter on Monday that it was building a "new pilot fuel enrichment plant" at an undisclosed site to produce low-enriched uranium. A senior Obama administration official in Washington, who requested anonymity because of the matter's sensitivity, said that Tehran sent the "non-transparent letter" after it apparently "caught wind of the fact . . . that others knew about this."
Obama said that the concealment of the site "underscores Iran's continuing unwillingness" to comply with five U.N. Security Council resolutions mandating that it suspend its enrichment activities. It's also "a direct challenge" to the Non-Proliferation Treaty, the cornerstone of the global system designed to halt the spread of nuclear weapons, he said.
The senior administration official in Washington said that Iran also must answer outstanding questions about materials presented to the IAEA several years ago by the U.S. indicating that Iranian experts conducted nuclear weapons-related research that U.S. intelligence analysts concluded was suspended in 2003.
Iran disputes the authenticity of the materials.
At the Oct. 1 talks in Geneva, Tehran must show that it's prepared to "take concrete steps to create confidence and transparency in its nuclear program and that it is committed to establishing its peaceful intentions," Obama said.
"We are already in a very severe confidence crisis," Sarkozy said. "Everything, everything must be put on the table now. We cannot let Iranian leaders gain time while the motors are running."
(Landay reported from Washington, Strobel from New York and Talev from Pittsburgh. Kevin G. Hall contributed to this article from Washington.)
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