White House spokesman Tony Snow sought to challenge earlier news reports about an intelligence report about the effects of the war in Iraq.
The National Intelligence Estimate on Iraq and terrorism represents the comprehensive consensus findings of 16 US intelligence agencies.
"It assesses that a variety of factors, in addition to Iraq, fuel the spread of jihadism, including longstanding social grievances, slowness of the pace of reform, and the use of the Internet," Mr Snow told reporters.
"And it also notes that should jihadists be perceived to have failed in Iraq, fewer will be inspired to carry on the fight," the spokesman said as US President George W. Bush travelled to Connecticut for a political fundraiser.
On Sunday, the New York Times quoted an official familiar with the report, entitled Trends in Global Terrorism: Implications for the United States, as saying that "the Iraq war has made the overall terrorism problem worse."
Mr Bush has been saying that the war made Americans safer as he campaigns ahead of November 7 legislative elections, in which the unpopular war in Iraq may cost his Republican party control of one or both houses of the US Congress.
The Washington Post said the report described the Iraq conflict as the primary recruiting vehicle for violent Islamic extremists.
While the US has seriously damaged al-Qaeda and disrupted its ability to carry out major operations since the September 11, 2001, attacks on New York and Washington, it noted, radical Islamic networks have spread and decentralised.
"One thing that the reports do not say is that war in Iraq has made terrorism worse," said Snow, who also insisted that the new reports "contain nothing that the president hasn't said."
He pointed to the news accounts saying that the NIE concluded that the leadership of Osama bin Laden's al-Qaeda network had been "hit hard" since it carried out the September 11, 2001 attacks on the United States.
Mr Snow also said the news reports described the NIE as finding that al-Qaeda had become more dispersed, with more independent activity, more use of the Internet and a shared "totalitarian ideology" with other terrorist groups.
Mr Bush has staunchly defended the US-led invasion of Iraq in March 2003, even though the weapons of mass destruction he cited as the principal reason to attack have never been found, and frequently says that "the world is better off without Saddam Hussein in power."
A senior adviser to Mr Bush, Dan Bartlett, told CNN that the NIE "doesn't make any final judgments to say that America is less safe or not because of this. It's just saying that they use this to use as a recruitment tool."
In an interview with Fox New Channel, Mr Bartlett said the war in Iraq was merely "the latest grievance" exploited by extremists to recruit followers.