This morning President Obama, French President Sarkozy, and British Prime Minister Gordon Brown will accuse Iran of building a clandestine underground nuclear fuel manufacturing plant, which Iran's leaders have hidden from weapons inspectors, senior administration officials tell ABC News.
Yesterday at the UN Security Council, all three leaders pressed the need for stronger sanctions against Iran for its nuclear weapons pursuits, but they were met with some resistance from China.
Today's announcement is being made to press their case, along with a demand that Iran allow inspectors from the International Atomic Energy Agency to see the facility, as first reported by the New York Times.
The president is expected to say that this news "increases pressure on Iran to come clean about its nuclear program," a senior administration official tells ABC News. He will described "great and increasing doubts about the strictly peaceful nature of the program -- which is what the Iranians suggest."
Over the summer US intelligence officials, working aggressively with the French and British had been preparing a case to present to the IAEA this week about the secret underground facility, officials say. Then recently the intelligence officials had "reason to believe that the Iranians thought the secrecy of the site was no longer guaranteed, and this week Iran's government wrote in a "vaguely worded letter to the IAEA apparently confessing to the construction of a new enrichment facility," one official says.
Asked if this would convince China of the need for stronger sanctions, the official said, "I don't know. I'm not going to jump to any conclusions. Obviously this increases pressure on Iran to come to the October 1 meeting in a position to say what it's doing and to suspend its program."
The IAEA's chief inspector, Olli Heinonen, has been briefed on the matter by US intelligence officials.
The Obama administration believes Iran has now lied to inspectors three times. In addition to today's news there were revelations in 2002 about a different clandestine plant, and news discovered in 2007 that Iran had been working to design a nuclear warhead.