Brig. Gen. Carter Ham said at a Pentagon news conference on Wednesday that Abu al-Masri, whose name surfaced shortly after reports of Zarqawi's death became widespread as a successor, had claimed to be in charge of Al Qaeda in Iraq.
"This individual said he is the successor for the leadership of Al Qaeda in Iraq," Ham said. "I think we'll have the intelligence effort in theater try to make that assessment if he is in fact exercising the leadership role in Al Qaeda in Iraq."
With several names emerging on Web sites and elsewhere, Ham said it's not clear whether they all refer to the same person.
"There is an individual who has claimed to be the successor to Zarqawi in Iraq," Ham said. "We have a variety of intelligence capabilities that will try to determine if there is an individual or individuals who are trying to step forward or exercise control."
An Islamic Web site Monday said a man named Abu Hamza al-Muhajer had been named to replace Zarqawi. A U.S. counterterrorism official said it's possible that this name could be an alias for al-Masri but said "we don't know for sure.
"It's not entirely clear whether this is a deliberate attempt to confuse or whether this is a name put out there as a placeholder of sorts. It is possible that this name could be the same person," the official said.
Zarqawi, the former leader of Al Qaeda in Iraq, was killed one week ago in a U.S. airstrike.