Iran's Revolutionary Guards admitted on Sunday for the first time that members of its elite Quds Force are in Syria, and warned Israel and Washington against any attack on the Islamic republic's nuclear sites.
In a rare Tehran news conference, Guards commander General Mohammad Ali Jafari said officials from the Quds Force - the Guards' special forces unit tasked with missions abroad - were active in both Syria and Lebanon to "counsel" forces fighting the Syrian opposition.
Iran was "proud of defending Syria, a member of the (anti-Israeli) resistance," Jafari said. "But it does not mean that we have a military presence there."
By designating the Quds Force members as advisors, not fighters, Jafari was maintaining Iran's denial of accusations by Western and Arab states that it was militarily shoring up the regime of embattled President Bashar al-Assad.
Jafari also spoke of the heightened tensions over Iran's disputed nuclear programme, which Israel has warned it could disrupt with air strikes, with or without US help.
Any attack on Iran would result in retaliation against the strategic Strait of Hormuz in the oil-rich Gulf, US military bases in the Middle East and Israel, he warned.
"This is a declared policy by Iran that if war occurs in the region and the Islamic republic is involved, it is natural that the Strait of Hormuz as well as the energy (market) will face difficulties," he said.
US military bases - such as those in Bahrain, Kuwait, Saudi Arabia and the United Arab Emirates - would equally be considered fair game.
"The US has many vulnerabilities around Iran, and its bases are within range of the Guards' missiles. We have other capabilities as well, particularly when it comes to the support of Muslims for the Islamic republic," he said.
Jafari explained that Tehran believed Israel was unsuccessfully trying to push the United States to take part in military action against Iran's nuclear facilities.
'Nothing of Israel would be left'
"I do not think the attack would be carried out without US permission," he said.
However if Israeli jets or missiles did strike Iran, "nothing of Israel would be left," he warned bluntly.
Anti-missile defence shields deployed by Israel and the United States in Arab states of the Gulf would be ineffective against a rain of Iranian missiles, he added.
"The defence shields may be capable against a few missiles, but they would not stand a chance against a massive number of missiles," he said.
But despite Israel's sabre-rattling, Iran had no intention of launching a pre-emptive strike, Jafari said.
"Iran does not believe in pre-emptive action to prevent a military strike... We are ready to respond to their attacks quickly and forcefully, and they are aware of our capabilities. This is our strongest deterrent."
Jafari also said that, in his opinion, any attack would prompt Iran to leave the nuclear Non-Proliferation Treaty which is designed to prevent states developing nuclear weapons while permitting peaceful atomic energy generation.
"In case of an attack, Iran's obligations will change. My assessment is that Iran may leave the NPT - but it would not mean a dash towards a nuclear bomb because we have a religious edict from the supreme leader" against atomic weapons, he said.