New York Times:

PITTSBURGH — President Obama and leaders of Britain and France accused Iran on Friday of building a secret underground plant to manufacture nuclear fuel, saying the country has hidden the covert operation from international weapons inspectors for years.
Appearing before reporters in Pittsburgh, Mr. Obama said that the Iranian nuclear program “represents a direct challenge to the basic foundation of the nonproliferation regime.” French President Nicholas Sarkozy, appearing beside Mr. Obama, said that Iran had deadline of two months to comply with international demands or face increased sanctions.
“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,” British Prime Minister Gordon Brown said, standing on the other side of Mr. Obama. “The international community has no choice today but to draw a line in the sand.”
The extraordinary and hastily-arranged joint appearance by the three leaders— and Mr. Obama said that German Chancellor Angela Merkel had asked him to convey that she stood with them as well — adds urgency to the diplomatic confrontation with Iran over its suspected ambition to build a nuclear weapons capacity. The three men demanded that Iran allow the International Atomic Energy Agency to conduct an immediate inspection of the facility, which is said to be 100 miles southwest of Tehran.