There are 50,000 buildings in Fallujah and each one has to be searched:
"Yesterday, one platoon of the Light Armored Reconnaissance company discovered a control center that could explode at least eight improvised explosive devices, the kind of roadside bombs that have inflicted large numbers of deaths across Iraq. The control center was set inside a normal building, with a wide horizon view of the main highway that cuts through the city. Each IED was labeled, and the operator had only to touch the copper wire for the battery to set off the explosive."
On Saturday the 1st Battalion, 8th Marines engaged in a serious battle in the south of Fallujah that killed two Marines and wounded several others. As the fight continued, Marines estimated that they had killed 34 insurgents and captured another 23, at least 10 of whom were foreign fighters.
Also Saturday, Bravo company of the 1st Battalion, 3rd Marines, found two vast weapons caches in the northeast of the city, which is considered to be the most "cleaned" so far, and therefore the most likely to see the earliest return of civilians.
"We've been through half the doors. It's a necessary but laborious process going on," says Col. Craig Tucker, commander of the Regimental Combat Team-7, one of two regiments active in Fallujah. "We'll go through every house in this city. We'll bring back people by sectors, but we don't want to bring people back while we are still finding 100 105 mm (artillery) rounds in a single house."
Honolulu Star-Bulletin Hawaii News