Iraqi government forces patrol the town of Mosul, Iraq, Thursday, May 15, 2008. Government troops began house-to-house searches for al-Qaida in Iraq militants in Mosul Thursday, part of a major security operation to cleanse Iraq's third-largest city from cells of the terror network. Described by the U.S. military as the last major urban base of al-Qaida in Iraq, Mosul has become the site of Prime Minister Nouri al-Maliki's third security drive in two months as he attempts to defeat Shiite militants and Sunni extremists. (AP Photo)