Washington Reporter

In a hastily arranged appearance before reporters in Pittsburgh on Friday morning, President Obama, along with British Prime Minister Gordon Brown and French President Nicolas Sarkozy, accused Iran of constructing a secret underground nuclear facility and hiding it from international weapons inspectors.
American officials have been monitoring the plant for years, but Obama decided to make it public after Iran learned that Western intelligence agencies had breached the facility's secrecy. Trying to play catch-up on Monday, Iran notified the International Atomic Energy Agency in a cryptic letter that it had a "pilot plant" under construction, which it had not previously revealed. On Friday, the agency confirmed that there is "a new pilot fuel-enrichment plant is under construction in the country." American officials said the plant could be in operation as soon as next year.
"The level of deception by the Iranian government, and the scale of what we believe is the breach of international commitments, will shock and anger the entire international community," Brown said after Obama made the initial announcement. "The international community has no choice today but to draw a line in the sand."
The unusual, confrontational press conference intensifies pending negotiations between Western leaders and Iran, which has repeatedly insisted that it is complying with weapons regulations. During his visit to the U.N. this week, President Mahmoud Ahmadinejad dismissed rumors of an Iranian nuclear program as fabrications.
Iran Said to Have Covert Nuclear Facility [New York Times]