The administration of U.S. President George W. Bush would likely spark a costly and unpredictable conflict should it strike Iran's nuclear sites, analysts said after reports that such strikes were under review.

According to Richard Haas, an expert at the Council on Foreign Relations (CFR), such strikes would be unlikely to remain "limited", as Tehran would also certainly retaliate.

"You cannot go into it assuming it will stay limited," Hass said at a CFR debate last week, adding "so very quickly, a limited military operation becomes a relatively unlimited military operation".

Separate articles in the New Yorker magazine and the Washington Post newspaper over the weekend re-sparked a controversial debate here over a potential U.S. military strike against Iran, with the media reports talking of possible air strikes against Iran's nuclear sites.

President Bush sought to downplay the articles, telling an audience Monday that Washington wants to settle the Iran nuclear crisis through diplomacy and calling the reports "wild speculation".

Kenneth Pollack, an expert at the Washington-based Brookings Institution think tank, said it's "highly likely" there would be a "furious" Iranian response to such assaults.

"You can't assume that if you take out their nuclear facilities that they are going to take it lying down and quiver and shake. You have to assume that they will come back and try to hurt you," Pollack said, addressing the same CFR debate.

"We can talk about a surgical strike where all we do is go in with a bunch of airplanes and flatten a few buildings. That's effectively what Osama bin Laden did on September 11th. And look at how we reacted," Pollack said.

He also cast doubt that the U.S. military could effectively destroy Iran's nuclear facilities, saying the facilities could easily be rebuilt.

"I believe a military strike would consolidate the hold of the Islamic government, not loosen it," said Joseph Cirincione, director of the Non-Proliferation Project at the Carnegie Endowment for International Peace.

Pollack said the 130,000 U.S. forces deployed across Iraq would be likely to face increased dangers if the U.S. launches strikes against neighboring Iran.

"The Iranians have very significant assets inside Iraq, they have a much greater capacity to inflict damage on us, on the Iraqis, on anybody else inside of Iraq, than the current crop of insurgents there," Pollack said.

Other observers have said that Iran might also react by closing off oil exports to the West or by launching an attack on Israel, which is widely believed to already possess nuclear weapons.