Iraqi armed forces and militia disguised as civilians and at times pretending to surrender only to fire on approaching coalition troops are causing planners of the U.S. air war to reevaluate their strategy. They say they need to find a way to support ground forces without weakening the strict rules of engagement that limit attacks on noncombatants.

"They are employing guerrilla tactics, and we are going to have to adapt," said Col. Jon Miclot, operations officer for the 3rd Marine Air Wing (MAW). "These pockets of resistance I think are going to present a problem to us," he added.

Other issues also facing planners are the need to improve time-sensitive targeting to engage a fleeing enemy before he can hide and monitor ground operations in nearby countries.

But the planners' first priority is grappling with "guerrilla tactics." Established rules of engagement mean pilots can't attack suspected militias or military troops disguised as civilians. "If they drive civilian trucks and [wear] civilian clothes, we are not going to drop [bombs]" until the forces reveal themselves as hostile, Miclot said.

The threat from guerrilla forces is causing the Marines to shift some of their weapon choices. For instance, the service expects to rely less on GPS-guided Joint Direct Attack Munitions and more on visual targeting as the Marines shift their attention to striking mobile targets. That will mean a greater emphasis on close air support from helicopters, primarily AH-1W Cobra gunships and laser-guided ordnance from fixed-wing aircraft. AV-8B pilots are considering the use of 5-in. rockets to attack individual vehicles or buildings with low-risk damage to surrounding areas.