The United States and its allies accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program, but Iran denied the U.S. charges and insists that its nuclear program is only for peaceful purposes.

The U.S. administration said it focused on diplomacy to try to resolve Iran's nuclear issue, but has insisted it will take "no option off the table."

A Pentagon official told The Sunday Times in London this week that Bush has given Israel an "amber light" to begin preparations for a military attack on Iran.

"Amber means get on with your preparations, stand by for immediate attack and tell us when you are ready," the unidentified Pentagon official was quoted as saying.

But the Israelis have also been told that they can expect no help from American forces and will not be able to use U.S. military bases in Iraq for logistical support, according to the report.

Nor is it certain that Bush's amber light would ever turn to green without irrefutable evidence of lethal Iranian hostility, The Sunday Times said.

"It's really all down to the Israelis," the Pentagon official said, adding that "Israel had not so far presented Bush with a convincing military proposal."

(Xinhua News Agency July 14, 2008)