US President George W Bush, who toppled the regimes in Afghanistan and Iraq, favours a similar policy towards Iran, according to a report.
But officials say he has not resolved how to aggressively pursue that aim, except to play down the option of using military force, according to the Wall Street Journal.
Hardliners in the Bush administration will call for a confrontational stance towards Iran if it does not take more steps against the Al Qaeda, it said.
"The US is particularly interested in the whereabouts of Saef al-Adel, an Egyptian militant linked to the Al Qaeda who US officials say is believed to have been in Iran recently," it said.
US officials claim they have intercepted telephone conversations believed to involve Adel or his associates from inside Iran discussing the May 12 car bombings in Riyadh in which 34 people, including eight Americans, were killed.
Some US officials argue that while Al Qaeda members appear to be in Iran, there is no evidence contradicting the Iranian government's claim that it is not assisting the group, according to the paper.
But others claim that Iran's Revolutionary Guards, who are known to support other terrorist groups such as Hezbollah, probably are providing some covert assistance to the Al Qaeda, it said.
Last year there were similar debates on whether Iraq was providing help to the Al Qaeda.
"It is unclear exactly what the full Iranian involvement within the Al Qaeda people is. There are certainly some in the administration who take a hard-core view, and others who say we don't know," the Journal quoted an intelligence official as saying.
In addition to the Al Qaeda's activities in the region, the paper said, much of the US-Iran tension these days has to do with events in Iraq.
Iranian officials have accused the US of failing to live up to its pre-war promises of eradicating the Mujaheddin-e-Khalq, an anti-Tehran group that for years has mounted cross-border attacks from Iraq.
Meanwhile, the Los Angeles Times said, "The war in Iraq has produced an unintended consequence -- a formidable Shiite Muslim geographical bloc that will dominate politics in the Middle East for many years.
"This development is also creating political and spiritual leaders of unparalleled international influence. It is easy to see the Shiite line-up. Iran and Iraq have a Shiite majority, and so does Bahrain. In Lebanon, Shiites are a significant plurality. In Syria, although they are a minority, they are the dominant power in the government.
"They are the majority in the eastern province of Saudi Arabia and have a significant presence in Afghanistan, Pakistan and India."