“You’ve got to be careful of unintended consequences here and those consequences could involve not only, not really deterring Iran from what they want to do, but more importantly it could have a serious impact in the region and it could have a serious impact on U.S. forces in the region," said Panetta.

Panetta said the US and its allies should instead toughen economic and diplomatic sanctions on Iran to change its behavior.

His warning follows the release this week of a report by the International Atomic Energy agency that says Iran may be carrying out secret experiments for the purpose of developing nuclear weapons.

The report bolstered calls by some in Israel’s government who have been calling for an attack on Iranian nuclear facilities sooner rather than later.

Meanwhile, Iran's Supreme Leader Ayatollah Seyyed Ali Khamenei said on November 10 that Iran will respond ‘powerfully’ to any attack on the country by the US and Israel, the semi-official Fars news agency reported.

"The enemies, especially the US and the Zionist regime (of Israel) should know that Iran does not aggress any country, but will respond to any aggression (on the Islamic Republic) and even to any threats (to the country) powerfully," Khamenei made the remarks while addressing Iranian army students.

"Anybody who may think of aggressions on the Islamic Republic should make itself ready to receive strong slaps and iron fists from Iranian Army, Islamic Revolution Guards Corps, (the voluntary forces of) Basij, and in one word from Iranian great nation," he was quoted as saying.

Khamenei called on Iran's Armed Forces to be prepared to defend the country.

VOA, Xinhua