A military source in Washington told The Times of London that Iranian President Mahmoud Ahmadinejad's claim of 3,000 centrifuges may be the "tipping point" that brings about an Israeli airstrike against Iranian nuclear facilities.

"Israel could do something when they get to around 3,000 working centrifuges.," a U.S. defense official said Wednesday, before the Iranian announcement. "The Pentagon is minded to wait a little longer."

U.S. experts said that number of working centrifuges could be used to construct a working atomic bomb within a year.

Efraim Inbar, of the Begin-Sadat Center for Strategic Studies in Tel Aviv, Israel, said the country is likely to take action if it appears Iran is approaching nuclear capability.

"I wouldn’t be surprised if we do something if the international community leaves us alone," he said to The Times. "I think we (Israel) are preparing for it. For Israel this is a critical technological moment."