Facing a major assault in Fallujah, insurgents struck back with coordinated attacks on police installations using suicide car bombs, mortars and rocket attacks, killing more than 50 people and wounding more than 60, including nearly two dozen Americans. The attacks could have been aimed at relieving pressure on Fallujah, where about 10,000 American troops are massing for a major assault. At dawn Sunday, rebels attacked police stations in western Anbar province, leaving 22 people dead, at least seven of them policemen, according to police and hospital officials. Using bombs and small arms fire, insurgents hit police stations in Haditha and Haqlaniyah, 135 miles northwest of Baghdad, said Capt. Nasser Abdullah of the K3 police station in Haqlaniyah.