US contingency plans for air strikes on Iran extend beyond nuclear sites and include most of the country's military infrastructure, the BBC has learned.
It is understood that any such attack - if ordered - would target Iranian air bases, naval bases, missile facilities and command-and-control centres.
BBC security correspondent Frank Gardner says the trigger for such an attack reportedly includes any confirmation that Iran was developing a nuclear weapon - which it denies.
Alternatively, our correspondent adds, a high-casualty attack on US forces in neighbouring Iraq could also trigger a bombing campaign if it were traced directly back to Tehran. Long range B2 stealth bombers would drop so-called "bunker-busting" bombs in an effort to penetrate the Natanz site, which is buried some 25m (27 yards) underground.
There is no doubt that there are those in the Bush administration who are simply aching to launch an attack on Iran. They and their neo-con allies outside of government have long sought to overthrow the Islamic regime in power, and they now find themselves with plenty of excuses in the issue of Iran's nuclear weapons and meddling in Iraq. It hardly surprises me then that the Bush administration would craft a bombing campaign that goes far beyond simply destroying Iran's nuclear capabilities. They wish to weaken Iran overall, and they secretly believe such a campaign would inflame the Iranian people and prompt them to overthrow their government (the exact opposite would happen of course.) However, the fact that such a campaign might also now be linked to a high-casualty attack on our forces in Iraq makes such an attack much more likely. What kind of attack are we talking about? How many casualties would be required? How clear must the Iranian fingerprints be? I would answer, not a very large one, not very many, and not clear at all. It is critical that we recognize that the Bush administration is merely looking for the pretext to attack Iran, and will do so with the confidence of misguided beliefs about the consequences. Since in their minds the situation in the Middle East can only be made better by such an attack, they are not worried about or deterred by political consequences at home. As certain as the anger of the American public might be to you and I, the Bush administration simply doesn't see it that way.
Therefore we must act to deter the administration before they can launch any sort of attack on Iran. Iran will by no means be able to acquire nuclear weapons while President Bush is still in office. Therefore it must be clear to the President and his staff that if an attack on Iran is conducted, impeachment will follow. They must understand that such a result is certain, and that the President will spend his remaining time in office trying to clean up a mess at and abroad. And you and I must push the Democrats on this issue, to take a certain stand against an attack on Iran at this time. The Presidential candidates can babble about leaving "all options on the table" if they want, but the leaders in Congress must be made to understand that they are the only deterrant to war with Iran. We must make them understand this.