Flanked by leaders of the world's most powerful nations, President Obama accused Iran of building a secret nuclear plant that he said is inconsistent with Tehran's denials of pursuing nuclear weapons.
"We are here to announce that yesterday in Vienna, the U.S., the United Kingdom and France presented detailed evidence ... demonstrating that the Islamic Republic of Iran has been building a secret uranium enrichment facility near Qom," said Obama, who is in Pittsburgh meeting with the leaders of the world's top 20 economies. "The existence of this facility underscores Iran's continuing unwillingness to meet its obligations."
Iranian President Mahmoud Ahmadinejad has said his nation's nuclear program is designed to produce energy, not weapons. But critics, including Israeli Prime Minister Benjamin Netanyahu, have scoffed at those claims. From Pittsburgh, Obama said there can be little doubt now that Ahmadinejad's claims are false.
"The size and configuration of this facility is not consistent with a peaceful program," Obama said of the underground plant.
Other foreign leaders, including Britain's Gordon Brown, French President Nicolas Sarkozy and German Chancelor Angela Merkel joined Obama in condemning Iran's treachery in pursuing nukes in secret.
"The level of deception by the Iranian government ... will shock and anger the whole international community and it will harden our resolve," said Brown.
Western intelligence services have known about the secret facility for years but kept quiet about it, even as the controversy built over Iran's nuclear ambitions, the New York Times reported. On Monday, Iran sent a letter disclosing a new "pilot plant" to the IAEA, a disclosure experts believe was prompted by Iran learning that Western governments knew about the plant.
In New York for the United Nations General Assembly, Ahmadinejad denied that the plant was secret or aimed at developing weapons. He said Obama will "be sorry" for his accusations.
"This is a mistake," Ahmadinejad said. "This is not how you enter negotiations. This is not nice."
"If I were President Obama's adviser, I would definitely advise him to refrain from making this statement, because it is definitely a mistake," he added.
The development came during the same week that longtime Iranian ally Russia signaled that it may be willing to go along with sanctions against Iran if it continues to deny international teams access to inspect its nuclear facilities. China, which can veto sanctions through its post on the UN Security Council, has not indicated that it would change its longstanding opposition to sanctions.
Separately, two unnamed government officials in Europe told The Associated Press that Iran revealed the existence of a second plant for enriching uranium in a letter sent Monday to International Atomic Energy Agency chief Mohamed ElBaradei.
Iran is currently under three sets of U.N. Security Council sanctions for its active uranium enrichment program and Ahmadinejad did not mention the facility in a speech this week before the global body. Iran will join nuke talks with the U.S. and other world powers on Oct. 1.
Get more: MSNBC, Politico