Special forces, also called special operations forces (SOF), are military units trained to conduct special operations. NATO has defined special operations as “military activities conducted by specially designated, organized, trained, and equipped forces, manned with selected personnel, using unconventional tactics, techniques, and modes of employment”. In the context of warfare during the 20th century, SOF missions included asymmetric warfare, counter-terrorism, deep recon, direct action, hostage rescue, operations behind enemy lines during time of war or ceasefire, protection of VIPs/dignitaries/STOL transport aircraft and irregular warfare.