About 600 U.S. Marines and Iraqi soldiers launched a fourth counter-insurgency operation in less than a month in a volatile western province in Iraq, this time near Fallujah, the military said Saturday. The counter-insurgency 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 Associated Press quoted the military as saying it did not announce the offensive earlier because commanders did not want to tip off insurgents that a major operation had begun.