Delta Force Delta Force The 1st Special Forces Operational Detachment-Delta (1st SFOD-D), commonly referred to as Delta Force, Combat Applications Group (CAG), "The Unit", Army Compartmented Element (ACE), or within JSOC as Task Force Green, is an elite special mission unit of the United States Army, under operational control of the Joint Special Operations Command. The unit is tasked with specialized missions primarily involving hostage rescue and counter-terrorism, as well as direct action and special reconnaissance against high-value targets. Delta Force and its maritime counterpart, the U.S. Navy's SEAL Team Six (also known as "DEVGRU"), are the U.S. military's primary counterterrorism units.
Counter-terrorism the militant Irish Fenians in the 1880s, the Home Secretary, Sir William Harcourt, established the first counter-terrorism unit ever. The Special Irish Branch was initially formed as a section of the Criminal Investigation Department of the London Metropolitan Police in 1883, to combat Irish republican terrorism through infiltration and subversion. Harcourt envisioned a permanent unit dedicated to the prevention of politically motivated violence through the use of modern techniques such as undercover infiltration. This pioneering branch was the first to be trained in counter-terrorism techniques. Its name was changed to Special Branch as it had its remit gradually expanded to