Hawks in the Bush administration have turned their sights on Iran, repeating accusations similar to those they deployed to portray Iraq as an imminent threat and win public support for war.
But this time moderates in the administration are likely to put up tougher opposition to military action against Iran or covert support for Iranian opposition groups, officials say.
ABC News said this week the US Defence Department wasadvocating a massive covert action program to overthrow the Iranian government as the only way to stop the country's nuclear program, which Washington claims is for making bombs.
A State Department official, who asked not to be named,said Defence Department hawks and allies in Washington'sneoconservative think tanks had not presented any formal plans but were encouraging such speculation in leaks to the media.
"What the neoconservatives do is they go to the media and then they tell us there are some interesting things we should look at in this or that report," said the official.
The term neoconservatives refers to ideologues in andaround the Bush administration who believe in the liberal use of military might abroad to serve US interests.
They are most strongly represented at the Pentagon, through Deputy Defense Secretary Paul Wolfowitz, Undersecretary Douglas Feith and William Luti, who is the deputy assistant secretary in charge of special plans, the Middle East and South Asia.
US Defence Secretary Donald Rumsfeld has charged Tehran wasnot doing enough against al Qaeda members allegedly in Iran and that the United States would "aggressively put down" any attempt by Iranian leaders to remake Iraq in Iran's image.
All branches of the Bush administration have complainedrepeatedly about Iran's nuclear programs, but State Department officials say they believe there is still room for diplomacy.
It was the same conjunction of links with "terrorists" and weapons of mass destruction that formed the rhetorical basis for the US invasion of Iraq in March.
The United States has since had trouble producing evidence of either.
The Bush administration had planned a high-level meeting to review Iran policy this week but it put off the talks indefinitely, amid deep internal divisions.
Michael Ledeen, one of the leading neoconservatives, put the hawkish view in the National Review Online on Tuesday. He said Iranian mullahs had an "active involvement" in the May 12 bombings on the Saudi capital Riyadh.
"Three days before the Riyadh attacks, 17 al Qaeda members were quietly moved to the Sistan and Baluchistan areas at the Pakistan border, hoping to conceal the Iranian connection, but it was uncovered anyway," he wrote.
State Department officials, who rely for information on their allies in the CIA, say such conclusions are premature.
"We're at the stage of analyzing what they are doing. ... First we have to decide what we know and then we can talk about options," one State Department official said.
Iran denies the al Qaeda charges.
"The recent arrests were made before the Riyadh explosions so, therefore, the accusations that the Riyadh explosions were controlled and planned from Iran are totally baseless.
Prisoners cannot control a military mission," Foreign Minister Kamal Kharrazi told a news conference on Friday.
Ledeen argued that the US "war on terrorism" had totarget Iran.
"It is impossible to win in Iraq or to block the spread of weapons of mass destruction throughout the terror network without bringing down the mullahs. ... If we are really serious about winning the war against terrorism, we must defeat Iran.
Thus far, we haven't been serious enough," he wrote.