Iraqi officials say a late night rocket attack on Baghdad\'s heavily fortified Green Zone has killed four Iraqis and wounded 10. A police officer says militants fired a Katyusha rocket late Monday night as Americans were celebrating Fourth of July at the U.S. Embassy, located in the Green Zone. The officer says the rocket hit a residential complex for laborers working at a hotel and sparked a fire. A doctor at a nearby hospital confirmed the causalities. Both spoke on condition of anonymity because they were not authorized to release information. The sprawling Green Zone houses Iraqi government headquarters and the U.S. and British embassies. It\'s a favorite target for insurgents\' mortar and Katyusha attacks.