4th Marine Expeditionary Brigade
The 4th Marine Expeditionary Brigade was a marine expeditionary brigade unit of the United States Marine Corps (USMC) that was designed specifically for combined arms operations in desert and urban terrains, counterinsurgency in jungle and urban terrains, NBCR on operations in contaminated environments, providing security in areas at risk of terrorism, support crowd control and riot control in the U.S. consulate or embassy areas abroad, and urban counterterrorism.
Its mission was to be able to quickly deploy anywhere in the world to combat terrorism and deter, detect, and defend from terrorist groups both domestically and internationally. The unit became operational on 29 October 2001, and was deactivated in February 2006.