Anti - Terrorism Battalion Anti - Terrorism Battalion ( ATBN ) was a specialized - infantry battalion in the United States Marine Corps . It was deactivated as of 2007 . Its reserve unit has not be disbanded & currently the unit falls under the 4th Marine Division as part of the Marine Forces Reserve . This unique unit possessed organic capabilities such as intelligence and counter - intelligence cells , combat engineers , enhanced nuclear , biological and chemical teams , and riflemen trained in advanced urban warfare . Note : ATBN is not to be confused with FAST Marines . Mission . On short notice , rapidly organize , train , and deploy specially trained and sustainable task forces to detect , deter , and defend against terrorism , as well as to conduct crisis response in the event of a terrorist attack . It also augmented existing units with additional capabilities such as organic combat engineers , advanced riflemen , and a human intelligence ( HUMINT ) exploitation team ( HET ) . Organization . Its components are organized as follows : History . Global War on Terror . Activation . The Battalion was activated in 2001 as a rotational unit responsibility as part of the USMC ' s 4th Marine Expeditionary Brigade ( AT ) along with Marine Corps Security Forces , CBIRF , Marine Corps Security Guard Battalion and other various units . 3rd Battalion 6th Marines , Commanding Officer LtCol Stephen W . Davis , was designated the Anti - Terrorism Battalion immediately after the 11 September attacks and began specialized training for rotations to Afghanistan . 3 / 6 ' s line companies began doing 3 - to 4 - month rotations in Afghanistan starting in December 2001 . Lima Company had the first rotation followed by Kilo and then India . These rotations continued for 3 / 6 until another infantry battalion took over . Other Marine Infantry battalions such as 3 / 2 , 1st Battalion 25th Marines ( 2003 ) , and 2 / 6 were rotated and designated as the " AT Bn " until 2005 when the official , separate , and permanent Anti - Terrorism Battalion was activated . The commissioning commanding officer was LtCol M . P . Killion . Transfer . The AT Battalion was transferred 24 February 2006 from the 4th Marine Expeditionary Brigade ( Anti - Terrorism ) to the 2nd Marine Division . 4th MEB ( AT ) was officially deactivated on the same date . The first commanding officer was LtCol . M . P . Killion . The second and last commanding officer was LtCol . R . C . Jackson . Training . Various schooling , in - house training , & courses attended 2004 - 2007 Extensive cross training between MOS & receiving passed down knowledge from FAST Company Marines . Note : Marines who cross trained in other MOS were not awarded their respective titles . Iraq . Between 2004 and 2007 , the AT Battalion had served in western Al Anbar , central Baghdad and northern Diyala provinces of Iraq . Deployments included : Numerous Marines also augmented other requirements for National Police Training Teams ( NPTT ) , Military Transition Teams ( MiTTs ) , and MEF augmentation requests to other infantry units when the battalion was redesignated the 2nd Bn 9th Marines . Most Marines in the Battalion completed two to three consecutive combat deployments in a single three year tour of duty with the battalion as part of their initial 4 year enlistment contract . Deactivation . On 13 July 2007 , The active duty ATBN was deactivated and replaced by 2nd Battalion 9th Marines as part of the increase in the size of the Marine Corps .