Newly appointed US Defence Secretary Leon Panetta told American troops in Baghdad on Monday that 9/11 was the reason they were in Iraq, before he was quickly corrected by his spokesman.
"The reason you guys are here is because of 9/11. The US got attacked and 3,000 human beings got killed because of Al-Qaeda," Panetta told about 150 soldiers at the Camp Victory US base.
"We've been fighting as a result of that," he said.
The administration of former US President George W. Bush had hastily linked Saddam Hussein, the ousted Iraqi dictator, to the 9/11 attacks.
That was one of the justifications for the 2003 US-led invasion, but the argument has since been widely dismissed.
Doug Wilson, Panetta's spokesman, quickly jumped in after his boss, who just took office on July 1, made the statement.
"I don't think he's getting into the argument of 2002-2003," as the reason for the Iraq invasion, Wilson he told reporters, adding that his boss was "a plain-spoken secretary."
"He has made clear that the major threat to this country is coming from Al-Qaeda and terrorist groups and he has also made clear that wherever we are in the world today, that (Al-Qaeda) is a principle reason for a military presence," Wilson said.
The new defence secretary also committed a faux pas in Afghanistan on Saturday, telling reporters the United States intends to keep 70,000 troops there until 2014.
President Barack Obama's administration has said it plans a steady withdrawal of US forces until the Afghans can take over their own security. Panetta's aides immediately retracted his remarks.
Panetta also told troops in Baghdad that the death of Al-Qaeda leader Osama bin Laden marked "one of the proudest moments of my life."
As CIA director, Panetta had overall responsibility for tracking down the elusive Al-Qaeda chief.