The United States Army Special Forces, also known as the Green Berets because of their distinctive service headgear, are a special operations force of the United States Army tasked with six primary missions: unconventional warfare, foreign internal defense, special reconnaissance, direct action, hostage rescue, and counterterrorism. The first two emphasize language, cultural, and training skills in working with foreign troops. Other duties include combat search and rescue (CSAR), security assistance, peacekeeping, humanitarian assistance, humanitarian demining, counterproliferation, psychological operations, manhunts, and counterdrug operations; other components of the United States Special Operations Command or other U.S. government activities may also specialize in these secondary areas. Many of their operational techniques are classified, but some nonfiction works and doctrinal manuals are available.

The original and most important mission of the Special Forces had been "unconventional warfare", while other capabilities, such as direct action, were gradually added.

Their official motto is De oppresso liber (Latin: To Liberate the Oppressed), a reference to one of their primary missions, training and advising foreign indigenous forces.

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