Delta Force 1st Special Forces Operational Detachment - Delta ( 1st SFOD - D ) , popularly known as Delta Force , is a U . S . Army component of Joint Special Operations Command . It was formerly listed as the Combat Applications Group by the Department of Defense but has since been officially re - designated the Army Compartmented Elements ( ACE ) . While 1st SFOD - D is administratively supported by USASOC , it falls under the operational control of the Joint Special Operations Command . Delta Force and its Navy counterpart , the Naval Special Warfare Development Group , are the United States military ' s primary counter - terrorism units . It is often referred to in the U . S . media as a Special Mission Unit . Delta Force ' s primary tasks are counter - terrorism , direct action , and national intervention operations , although it is an extremely versatile group capable of conducting many types of clandestine missions , including , but not limited to , hostage rescues and raids . The Central Intelligence Agency ' s highly secretive Special Activities Division ( SAD ) and more specifically its elite Special Operations Group ( SOG ) often works with – and recruits – operators from Delta Force . History . Delta Force was formed after numerous , well - publicized terrorist incidents in the 1970s . These incidents led the U . S . government to develop a full - time counter - terrorism unit . Key military and government figures had already been briefed on a model for this type of unit in the early 1960s . Charlie Beckwith , a Special Forces officer and Vietnam veteran , had served as an exchange officer with the British Army ' s Special Air Service ( 22 SAS Regiment ) during the Malayan Emergency . Upon his return , Beckwith presented a detailed report highlighting the U . S . Army ' s vulnerability in not having an SAS - type unit . U . S . Army Special Forces in that period focused on unconventional warfare , but Beckwith recognized the need for " not only teachers , but doers . " He envisioned highly adaptable and completely autonomous small teams with a broad array of special skills for direct action and counter - terrorist missions . He briefed military and government figures , who were overtly resistant to create a new unit outside of Special Forces , or change existing methods . Finally , in the mid - 70 ' s , as the threat of terrorism grew , Pentagon brass tapped Beckwith to form the unit . Beckwith had estimated that it would take 24 months to get his new unit mission - ready . Beckwith ' s estimate is due to a conversation he had earlier with Brigadier John Watts while updating his SAS experience in England in 1976 . Watts had made it clear to Beckwith that it would take eighteen months to build a squadron , but advised him to tell the Army brass that it would take two years , and to not ' let anyone talk ( him ) out of this . ' To justify why it would take two years to build Delta , Beckwith and his staff drafted what they curiously dubbed the " Robert Redford Paper . " In it Delta outlined its necessities and historical precedents for a four - phase selection / assessment process . In the meantime , Colonel Bob " Black Gloves " Mountel of the 5th Special Forces Group was tasked with creating a unit ' to breach the short - term gap ' that existed until Delta was ready , dubbed Blue Light . On 4 November 1979 , shortly after Delta had been created , 53 Americans were taken captive and held in the U . S . embassy in Tehran , Iran . The unit was assigned to Operation Eagle Claw and ordered to covertly enter the country and recover the hostages from the embassy by force on the nights of 24 and 25 April in 1980 . The operation was aborted due to aviation failures . The review commission that examined the failure found 23 problems with the operation , among them unbriefed weather encountered by the aircraft , command - and - control problems between the multi - service component commanders , a collision between a helicopter and a ground - refueling tanker aircraft , and mechanical problems that reduced the number of available helicopters from eight to five ( one fewer than the minimum desired ) before the mission contingent could leave the trans - loading / refueling site . After the failed operation , the U . S . government realized more changes needed to be made . The 160th Special Operations Aviation Regiment ( Airborne ) , also known as the " Night Stalkers " , was created specifically for special operations requiring aviation support . The Navy ' s Special Warfare Development Group , formerly designated Seal Team Six , was created for maritime counter - terrorism operations . The Joint Special Operations Command was created for command and control of the various counter - terrorism units of the U . S . military . Organization and structure . The unit is under the organization of the US Army Special Operations Command ( USASOC ) but is controlled by the Joint Special Operations Command ( JSOC ) . Command of 1st SFOD - D is a Colonel ' s billet . Virtually all information about the unit is highly classified and details about specific missions or operations are generally not publicly available . A number of sources including the book " Inside Delta Force " by Command Sergeant Major Eric L . Haney ( ret . ) , suggest the unit ' s strength ranges from between 800 to 1000 personnel , including the following operational groups : Detachment designations . Delta Force ' s structure is similar to the British 22 Special Air Service , the unit which inspired Delta ' s formation . In " Not a Good Day to Die : The Untold Story of Operation Anaconda " , " Army Times " staff writer Sean Naylor describes Delta as having nearly 1 , 000 soldiers . Naylor wrote that approximately 250 of those are operators trained to conduct direct action and reconnaissance missions . There are three main operational squadrons : These squadrons are based on the organization of the SAS " Sabre Squadron " and each contains 75 to 85 operators . Each sabre squadron is broken down into three troops — one recon / sniper troop , and two direct action / assault troops — that can either operate in teams or in groups as small as four to six men . Recruitment . Most recruits come from the Special Forces Groups with a sizable but significantly smaller portion hailing from the 75th Ranger Regiment , but some operators have come from other units of the army . Since the 1990s , the Army has posted recruitment notices for the 1st SFOD - D . The Army , however , has never released an official fact sheet for the force . The recruitment notices placed in Fort Bragg ' s newspaper , " Paraglide " , refer to Delta Force by name , and label it " . . . the U . S . Army ' s special operations unit organized for the conduct of missions requiring rapid response with surgical application of a wide variety of unique special operations skills . . . " The notice states that all applicants must be male , in the ranks of E - 4 through E - 8 , have at least two and a half years of service time remaining in their enlistment , be 21 years or older and score high enough on the Armed Services Vocational Aptitude Battery test to attend a briefing to be considered for admission . On 29 June 2006 during a session of the Committee on Armed Services , General Wayne Downing testified before the U . S . House of Representatives that 70 % of all Delta operators started their military careers in the 75th Ranger Regiment . Selection process . Haney ' s book " Inside Delta Force " described the selection course and its inception in detail . Haney writes the selection course began with standard tests including push - ups , sit - ups , and a run , an inverted crawl and a 100 meter swim fully dressed . The selection candidates are then put through a series of land navigation courses to include an , all - night land navigation course while carrying a rucksack . The rucksack ' s weight and the distance of the courses are increased and the time standards to complete the task are shortened with every march . The physical testing ended with a march with a rucksack over very rough terrain which had to be completed in an unknown amount of time . Haney wrote that only the senior officer and NCO in charge of selection are allowed to see the set time limits , but all assessment and selection tasks and conditions were set by Delta training cadre . The mental portion of the testing began with numerous psychological exams . The men then went in front of a board of Delta instructors , unit psychologists and the Delta commander , who each ask the candidate a barrage of questions and then dissect every response and mannerism of the candidate with the purpose to mentally exhaust the candidate . The unit commander then approaches the candidate and tells him if he has been selected . If an individual is selected for Delta , he undergoes an intense 6 - month Operator Training Course ( OTC ) , to learn counter - terrorism and counter - intelligence techniques , in which the individual maintains very little contact with friends and family for the duration . Training includes firearm accuracy and various other munitions training . In a recent interview , former Delta operator Paul Howe talks about the high attrition rate of his Delta selection course . He says that of roughly 240 men , 16 candidates were selected for the Operator Training Course ( OTC ) . Following OTC , only 12 to 14 candidates successfully completed the course . Training . Operator Training Course : According to the book " Inside Delta Force " by Eric Haney , OTC consisted of the following events . Although OTC has probably changed since then , it remains around 6 months long . Although these are the main skills taught in every OTC , no OTC classes are ever exactly the same . Delta Force occasionally cross - trains with similar units from allied countries such as the Australian SASR , British SAS , Canadian JTF2 , French GIGN and 1st RPIMa , German KSK , Israeli Sayeret Matkal , Mexican FEAM and Polish GROM . They cross train and deploy with US Naval Special Warfare Development Group ( DEVGRU ) . They have helped train other U . S . counter - terrorism units , such as the FBI ' s Hostage Rescue Team and Joint Military / Government Agency Unit Task Force 6 - 26 . Commanding officers . Command of 1st SFOD - D is a Colonel ' s billet . Uniform . The Pentagon tightly controls information about Delta Force and publicly refuses to comment on the highly secretive unit and its activities . Delta operators are granted an enormous amount of flexibility and autonomy . To conceal their identities , they rarely wear a uniform and usually wear civilian clothing both on and off duty . When military uniforms are worn , they lack markings , surnames , or branch names . Civilian hair styles and facial hair are allowed to enable the members to blend in and avoid recognition as military personnel . The term " operator " . Inside the United States Special Operations community , an " operator " is a Delta Force member who has completed selection and has graduated OTC ( Operators Training Course ) . " Operator " was first used by Delta Force to distinguish between operational and non - operational personnel assigned to the unit . Other special operations forces use specific names for their jobs ( Army " Rangers " , Navy " SEALs " , Air Force " Pararescuemen " ) ; " operator " is the specific term for Delta ' s operational personnel . However , since the early 2000s other special operations forces have adopted the term . SEALs have unofficially referred to themselves as operators since the Vietnam War . Author and Navy SEAL Gene Wentz makes many references to fellow SEALs as operators in his 1992 book titled " Men In Green Faces , " which is about the SEALs in Vietnam . Operations and clandestine operations . The majority of the operations assigned to Delta are classified and may never be known to the public . However , details of some operations have become public knowledge . There have been many occasions that Delta have been put on standby and operational plans developed but the unit was stood down for various reasons .