The U.S. military conducted more than five times as many airstrikes in Iraq last year as it did in 2006, targeting al-Qaeda safe houses, insurgent bombmaking facilities and weapons stockpiles in an aggressive strategy aimed at supporting the U.S. troop increase by overwhelming enemies with air power.

Top commanders said that better intelligence-gathering allows them to identify and hit extremist strongholds with bombs and missiles, and they predicted that extensive airstrikes will continue this year as the United States seeks to flush insurgents out of havens in and around Baghdad and to the north in Diyala province.