The operation would target training camps and munitions factories that assist Iraqi insurgents, Hezbollah and terrorist groups in Gaza, DEBKAfile.com, a military intelligence Web site, reported Tuesday, quoting sources in Washington.
U.S. President George Bush in May said talk of a military action of some kind against Iran is "highly speculative."
"I've always made it clear that options are on the table, but, you know, the biggest weapon we have against those who can't stand freedom is the advance of freedom," he said.
Iran reportedly is preparing counter measures, perhaps on a larger scale, the Web site said.
"Iran's Armed Forces are fully prepared to counter any military attack with any intensity and to make the enemy regret initiating any such incursions," Iran defense minister Gen. Mostafa Mohammad-Najjar said Sunday.
The Revolutionary Guard has completed preparations for a U.S. attack on their bases, DEBKAfile.com said, and have evacuated training camps and bases.