In his first public appearance, CIA Director Porter Goss on Wednesday described armed groups fighting US forces in Iraq as inspired by Usama bin Ladin and intent on attacking Americans.
"The Iraq conflict, while not a cause of extremism, has become a cause for extremists," Goss said.
"Those jihadists who survive will leave Iraq experienced in and focused on acts of urban terrorism. They represent a potential pool of contacts to build transnational terrorist cells, groups and networks in Saudi Arabia, Jordan and other countries," he said.
US President George Bush cited Iraqi backing for international terrorism as a reason for invading the country.
"The Iraq conflict, while not a cause of extremism, has become a cause for extremists"
His critics, however, had always maintained the invasion was a distraction from the global "war against terror" declared after the 11 September 2001 attacks on the US.
"These sentences indicate Goss is very much listening to what his analysts are saying and not necessarily to what the White House wants to hear," said Kenneth Katzman, terrorism analyst for the Congressional Research Service.
Goss also said those fighting US forces in Iraq had achieved some of their goals in the Iraqi elections by keeping Sunni Arab voter turnout low.
A long-time intelligence officer and former chairman of the House of Representatives intelligence committee, Goss took over as the head of the CIA last year.
He said US authorities and their allies had dealt "serious blows" to the al-Qaida network.
"Despite these successes, however, the terrorist threat to the US in the homeland and abroad endures," he warned.