Mosul is a centre for al-Qaeda fighters displaced from further south
The US military in Iraq says a militant killed on Tuesday has been positively identified as the leader of al-Qaeda in the city of Mosul.
It said the man - identified by a pseudonym, Abu Khalaf - had co-ordinated and ordered many attacks.
He was shot dead by American troops during a raid on a building in Mosul.
US and Iraqi forces have been carrying out an offensive in the city for more than a month, in an attempt to drive out al-Qaeda in Iraq from Mosul.
The city, US and Iraqi officials say, is al-Qaeda's last urban stronghold in Iraq.
Also on Friday, US military officials said the handover to Iraqi control of Anbar province, west of Baghdad, was being postponed.
A statement said the delay was because of forecasts for high winds and dust storms on Saturday, but no new date for the handover was announced.
The postponement came a day after a suicide bomb attack in Anbar, which killed at least 20 people, including a tribal leader and members of a patrol force opposed to al-Qaeda in Iraq.