The United States and its allies began their largest ever naval exercise in the Middle East on Sunday, designed to demonstrate their ability to counter a potential Iranian naval blockade of the vital Straight of Hormuz.

An armada of military hardware from 25 nations, including battleships, aircraft carriers, submarines and minesweepers has descended on the Persian Gulf as Western policy makers desperately try to convince Israel that diplomacy and sanctions designed to halt Iran's nuclear program need more time to work.

The massive show of force has once again brought the threat of war to the region, raising the prospect Israel will launch a pre-emptive strike against Iran, which has already promised retaliation for any attacks against its nuclear facilities.

On Sunday, the Associated Press quoted Iran's top revolutionary Guard commander Gen. Mohammad Ali Jafari as waring that: "His country's missiles will ensure 'nothing will remain' of Israel if it takes military action against Tehran over its controversial nuclear program."

Predicting a joint U.S./Israeli attack, Jafari added that he was also prepared to strike American bases in the region.

And while American officials have downplayed the naval exercise as being "focus[ed] on a hypothetical threat from an extremist organization to mine the international strategic waterways of the Middle East," some commentators see the exercise -- which lasts until 27 September -- as a precursor to something far more immediate.

"An armada of US and British naval power is massing in the Persian Gulf in the belief that Israel is considering a pre-emptive strike against Iran's covert nuclear weapons programme," warned the Daily Telegraph's defense correspondent Sean Rayment on Monday.

"Battleships, aircraft carriers, minesweepers and submarines from 25 nations are converging on the strategically important Strait of Hormuz in an unprecedented show of force as Israel and Iran move towards the brink of war," Rayment wrote.

"In preparation for any pre-emptive or retaliatory action by Iran, warships from more than 25 countries, including the United States, Britain, France, Saudi Arabia and the UAE, will today begin an annual 12-day exercise."

But others caution that Iran is unlikely to mine the vital sea lanes of Hormuz as they would too would be hit by the resulting oil blockade.

"They would be hurting themselves the most because they would be cutting off their main source of revenue, which is oil exports, at a time when they are already being sanctioned heavily and money is tight," Karim Sadjadpour, a senior associate at the Carnegie Endowment for International Peace, told PBS.

Iran would have only two reasons to mine the Straight, according to Sadjadpour.

"In the event of a [Israeli] military attack, there is more than [a] 50 percent chance they would attempt to close the strait or prevent others from passing through freely," he added.

"They don't have that many options for retaliation. They can try to launch missiles into Saudi Arabia to spike oil prices; they can try to unleash Hezbollah and Hamas; and, if they want to hurt the world, it's by closing the strait."

Secondly, if all their oil export options were closed then they would have nothing to lose by blockading Hormuz.

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