About 600 U.S. Marines and Iraqi soldiers launched a fourth counterinsurgency operation in less than a month in a volatile western province in Iraq, this time near Fallujah, the military said Saturday. The counterinsurgency offensive, called Operation Scimitar, started Thursday with targeted raids in Zaidan, 19 miles southeast of Fallujah. Two days later, 22 suspected insurgents had been detained. The military said it did not announce the offensive earlier because commanders did not want to tip off insurgents that a major operation had begun. The offensive - named after a curved sword - includes 500 Marines from the 3rd Reconnaissance...