It is being reported the US may have moved a step closer to military action against Iran, but there has also been a change in the potential target.

A new report suggests the target of any attack would be Iran's Revolutionary Guard, rather than the country's nuclear facilities.

Pulitzer Prize-winning journalist Seymour Hersh has been writing about the possibility of a US strike on Iran for the past 18 months.

In his latest article for The New Yorker magazine and in a TV interview, he has gone on to claim that Australia has "expressed interest" in the concept.

Public unconvinced

In his latest article for The New Yorker he argues the Bush administration has acknowledged the American public is not convinced Iran poses an imminent nuclear threat.

At the same time, he says there is a renewed focus on the increasing number of attacks on coalition forces in Iraq, and claims that Iranian munitions are playing a key role.

This was part of a speech by President George W Bush in late August.

"The attacks on our bases and our troops by Iranian supplied munitions have increased in the last few months, despite pledges by Iran to help stabilise the security situation in Iraq," Mr Bush said in the speech.

"I will take actions necessary to protect our troops, I have authorised our military commanders in Iraq to confront Tehran's murderous activities."

Mr Hersh cites this rhetoric as evidence of the changing tone coming out of the Bush administration.

"The name of the game used to be that they're a nuclear threat, Iran is going to have a bomb soon, we have to do it, sort of the same game we had before the war in Iraq," he said.

"What's happened is that in that last few months they've come to the realisation that's it's not selling, the American people aren't worried about Iran as a nuclear threat, certainly as they were about Iraq, there's just some scepticism.

"So they've switched, really."

Mr Hersh says he believes there is now a consensus within the American public that if the Iranians are actively pursuing plans to develop a nuclear weapon, they are at least five years away from their goal.

He says that has tipped the shift in the administration's approach.

"Instead of trying to sell it, not only to the American people but to its allies, the notion of a massive bombing against the infrastructure, what they call counter-proliferation against the infrastructure of the Iraqi bomb, hitting the various facilities that we know exist - instead, they've now decided that they're going to hit the Iranians, payback for hitting us," he said.

"They're going to hit the Revolutionary Guard headquarters and facilities, they're going to tone down the bombing, they're going to shift it. It's going to be more surgical."

Mr Hersh says the new strategy involves a subtle change of targets.

"We're threatening Iran, we've been doing it constantly, but instead of saying to the American people and instead of saying internally, 'It's going to be about nuclear weapons', it's now going about getting the guys that are killing our boys," he said.

"We're going to hit the border facilities, the facilities inside Iraq that we think are training terrorists, we're going to hit the facilities we think are supplying some of the explosive devices into Iraq.

"This is the administration's position."

Australia on board?

He also claims the Bush administration's new focus is getting support from its allies, including Australia.

"The Brits are interested in this idea, there have been expressions of interest from Australia, other countries, the Israelis of course have gone bananas, they're very upset about the idea of not going," he said.

"If you're going to go into Iran, the Israeli position is very firm, they want us to go, and they want us to hit hard. ... An Israeli told me, if you run into a lion, you either shoot it, or ignore it, you don't pluck out its eyebrows.

"Going in and taking out the Revolutionary Guard and not taking out the nuclear facilities, for the Israelis is it a non-starter.

"But that's the plan, the plan is to be more surgical, more careful, and they're getting some of their allies on board."

Last week, Foreign Affairs Minister Alexander Downer said he called on Iran to stop supplying weapons to militias in Iraq during a recent bilateral meeting with Iran's Foreign Minister.

A spokesman for the Minister's office declined to respond to Mr Hersh's latest claims.

'The opening gambit'

Dr Michael McKinley, a senior lecturer in International Relations and Strategy at the Australian National University, says a US attack would lead to war.

"If the United States was to engage in surgical strikes, as some people are once again talking about, you would have to say that Iran could very well behave in such a way, and there'd be a broad scope of possibilities here, where a widely escalated war would need to ensue after that, because I cannot imagine that Iran would just allow itself to be attacked without taking some sort of forceful reaction," he said.

He is unconvinced an attack on Iran would stop with 'surgical strikes'.

"You have to challenge the logic of it, because if you attack Iran because it seems to be supporting activities inside Iraq, then by the logic that everybody in the decision-making framework seems to have, Iran would then speed up its alleged nuclear weapons program," he said.

"That would be the logical way of regarding an Iranian reaction, which would then of course require a further and much stronger reaction on its nuclear sites from the United States.

"So this would appear to be only the opening gambit, rather than a one-off, if you take everybody's logic at face value."

Dr McKinley says he believes there there is a disposition in the US administration to take some form of military action against Iran.

"I would be more surprised rather than less surprised if there was not an attack sometime before the Bush administration leaves office," he said.

Mr Hersh agrees.

"What I do know, is he wants to do something," he said.

"He will not leave Iran in a position to be a nuclear power and a position to be a threat."