The US administration may understand that its sanctions announced Thursday will have limited effect, and is in fact laying the ground for military action against the oil-rich Islamic state, experts on US-Iran relations said.

"I'm skeptical about if it will have any impact on all, primarily because the US unilaterally has very limited leverage over the Iranian state, economy and armed forces," said Alex Vatanka at Jane's Information Group.

"You only have to look at past behavior from the Russians, the Chinese and to some extent the Europeans to feel skeptical about how much other countries around the world will rally to the US on this," he told AFP.

"To get Iran to change its behavior in a positive way, you have to give it something. This is all sticks. There's no sign of a carrot here."

The US sanctions target the Islamic Revolutionary Guard Corps (IRGC), which was accused of spreading weapons of mass destruction, and the IRGC's elite Quds Force, which was designated as a supporter of terrorism.

Three of Iran's biggest state-owned banks -- Melli, Mellat and Saderat -- were also designated as the United States stepped up a drive to squeeze Iran out of the international banking system.

Saderat was already blacklisted by the US government on more limited grounds in September 2006. Several Japanese banks reportedly cut ties with the bank, while Swiss giant UBS ceased its business activities in Iran last year.

"It is plain and simple -- reputable institutions do not want to be bankers to this dangerous regime," Treasury Secretary Henry Paulson said.

But the United States has been frustrated by Russian and Chinese reluctance to impose a third round of UN sanctions over Iran's nuclear program. For the US banking measures to have teeth, more European lenders must come on board.

A senior administration official said that Washington had conducted "an extraordinary amount of outreach" to European governments and banks with extensive commercial interests in Iran.

The response had been "very cooperative" from banks that want "to protect their reputation," he said, on condition of anonymity.

A broad US economic embargo imposed following Iran's Islamic revolution of 1979 has had only a limited effect on changing Tehran's policies.

In targeting the IRGC and Quds Force, the United States was for the first time directly sanctioning another country's military -- a step that Vatanka warned could put the country "on the slippery slope" to war with Iran.

President George W. Bush suggested last week a nuclear-armed Iran could trigger "World War III" and Vice President Dick Cheney spoke on Sunday of "serious consequences" unless the Islamic republic comes to heel.

Meanwhile on the 2008 campaign trail, Republican presidential candidates have vied with Democratic front-runner Hillary Clinton to claim the mantle of toughest hawk on Iraq.

Secretary of State Condoleezza Rice renewed an offer to meet her Iranian counterpart for talks "anytime, anywhere" and on any issue if Tehran agrees to suspend its uranium enrichment.

But for Manochehr Dorraj, professor of international relations at Texas Christian University, there may be a hidden agenda to the new sanctions.

Their effectiveness hinges "in large measure" on the cooperation of European allies such as France and Germany, and Russia and China, "which have even closer political and financial ties with Tehran," he said.

"But should the Iranians remain unresponsive, then the Bush administration may use this as a pretext to argue that the sanctions have not worked to convince the Iranian government to halt its uranium enrichment activities, and that the military option is the only viable alternative," Dorraj added.

In Washington, the anti-war Center for Arms Control and Non-Proliferation said the unilateral sanctions would trigger a "backlash" from President Mahmoud Ahmadinejad and other hardliners in the Iranian regime.

"One thing that is particularly troubling about this move is that the administration is viewing it as part of its diplomatic effort," said Carah Ong, the center's Iran policy analyst, calling the sanctions "punitive" instead.

related report
US military conducting 'routine' contingency planning on Iran
The United States is conducting "routine" contingency planning for military options against Iran, US Defense Secretary Robert Gates said Thursday.

Gates, speaking to reporters on a flight here from Europe, was asked the state of US military planning and whether it had gone beyond routine contingency planning.

"I would characterize it as routine," he said.

"The focus we all have is on using on diplomatic pressure and economic sanctions to persuade the Iranian government that they are isolated, they need to alter their policies and ambitions," he said.

related report
US statements on Iran and Iraq, then and now
While the US administration insists it is pursuing diplomacy in its disputes with Iran, critics of President George W. Bush see worrying parallels between recent statements on Tehran and the run-up to the war in Iraq.

The Bush administration announced new sanctions against Iran on Thursday, accusing the regime of backing terrorists, supporting insurgents in Iraq and working to build an atomic arsenal.

The following are recent comments by Bush and Vice President Dick Cheney on Iran's nuclear program and statements on Iraq made prior to the 2003 US-led invasion.

IRAN

"The Iranian regime needs to know that if it stays on its present course, the international community is prepared to impose serious consequences."

-- Vice President Dick Cheney speaking to the Washington Institute for Near East Policy on October 21, 2007.

IRAQ

"The Council has repeatedly warned Iraq that it will face serious consequences as a result of its continued violations of its obligations."

-- UN Security Council Resolution 1441, adopted in 2002, which the Bush administration says authorized the March 2003 invasion of Iraq.

IRAN

"We got a leader in Iran who has announced that he wants to destroy Israel. So I've told people that if you're interested in avoiding World War III, it seems like you ought to be interested in preventing them from have the knowledge necessary to make a nuclear weapon."

-- Bush speaking in a press conference on October 17, 2007.

"Iran's active pursuit of technology that could lead to nuclear weapons threatens to put a region already known for instability and violence under the shadow of a nuclear holocaust. Iran's actions threaten the security of nations everywhere. And that is why the United States is rallying friends and allies around the world to isolate the regime, to impose economic sanctions. We will confront this danger before it is too late."

-- Bush in a speech to the annual American Legion convention on August 28, 2007.

IRAQ

"Facing clear evidence of peril, we cannot wait for the final proof -- the smoking gun -- that could come in the form of a mushroom cloud."

-- Bush in a speech on Iraq in Cincinnati on October 7, 2002.

IRAN

"Our intelligence community assesses that, with continued foreign assistance, Iran could develop an intercontinental ballistic missile capable of reaching the United States and all of Europe before 2015. If it chooses to do so, and the international community does not take steps to prevent it, it is possible Iran could have this capability. And we need to take it seriously -- now."

-- Bush in a speech to the National Defense University on October 23, 2007.

IRAQ

"If the Iraqi regime is able to produce, buy, or steal an amount of highly enriched uranium a little larger than a single softball, it could have a nuclear weapon in less than a year. And if we allow that to happen, a terrible line would be crossed. Saddam Hussein would be in a position to blackmail anyone who opposes his aggression. He would be in a position to dominate the Middle East. He would be in a position to threaten America. And Saddam Hussein would be in a position to pass nuclear technology to terrorists."

-- Bush in the speech on Iraq in Cincinnati on October 7, 2002.

IRAN

"Our struggle is not with the Iranian people. As a matter of fact, we want them to flourish, and we want their economy to be strong. And we want their mothers to be able to raise their children in a hopeful society. My problem is with a government that takes actions that end up isolating their people and ends up denying the Iranian people their true place in the world."

-- Bush congratulating General David Petraeus on his confirmation as commander of forces in Iraq on January 26, 2007.

IRAQ

"The Iraqi people cannot flourish under a dictator that oppresses them and threatens them. Gifted people of Iraq will flourish if and when oppression is lifted."

-- Bush signing the authorization to use military force in Iraq on October 16, 2002.

IRAN

"All options are on the table. I would hope that we could solve this diplomatically."

-- Bush, meeting with Israeli Prime Minister Ehud Olmert on June 19, 2007.

"The United States joins other nations in sending a clear message: We will not allow Iran to have a nuclear weapon."

-- Cheney in the October 21, 2007 speech.

IRAQ

"All options are on the table, and -- but one thing I will not allow is a nation such as Iraq to threaten our very future by developing weapons of mass destruction."

-- Bush speaking at a press conference on March 13, 2002, a year before military action against Iraq.