Special forces emerged in the early 20th century, with a significant growth in the field during the Second World War, when "every major army involved in the fighting" created formations devoted to special operations behind enemy lines. Depending on the country, special forces may perform functions including airborne operations, counter-insurgency, counter-terrorism, foreign internal defense, covert ops, direct action, hostage rescue, high-value targets/manhunting, intelligence operations, mobility operations, and unconventional warfare.
In the United States the term special forces often refers specifically to the US Army's Special Forces, while the term special operations forces (SOF) is used more broadly for these types of unit. In Russian-speaking countries special forces of any country are typically called spetsnaz, an acronym for "special purpose".
Special forces capabilities include the following:
Special forces have played an important role throughout the history of warfare, whenever the aim was to achieve disruption by "hit and run" and sabotage, rather than more traditional conventional combat. Other significant roles lay in reconnaissance, providing essential intelligence from near or among the enemy and increasingly in combating irregular forces, their infrastructure and activities.