A death squad is an armed group whose primary activity is carrying out extrajudicial killings or forced disappearances as part of political repression, genocide, ethnic cleansing, or revolutionary terror. Except in rare cases in which they are formed by an insurgency, domestic or foreign governments actively participate in, support, or ignore the death squad's activities. Death squads are distinct from assassination from their permanent organization and the larger number of victims (typically thousands or more) who may not be prominent individuals. Other violence, such as rape, torture, arson, or bombings may be carried out alongside murders. They may comprise a secret police force, paramilitary militia groups, government soldiers, policemen, or combinations thereof. They may also be organized as vigilantes, bounty hunters, mercenaries, or contract killers. When death squads are not controlled by the state, they may consist of insurgent forces or organized crime, such as the ones used by cartels.
Although the term "death squad" did not rise to notoriety until the activities of such groups became widely known in Central and South America during the 1970s and 80s, death squads have been employed under different guises throughout history. The term was first used by the fascist Iron Guard in Romania. It officially installed Iron Guard death squads in 1936 in order to kill political enemies. It was also used during the Battle of Algiers by Paul Aussaresses.
In Latin America, death squads first appeared in Brazil where a group called Esquadrão da Morte (literally "Death Squad") emerged in the 1960s; they subsequently spread to Argentina and Chile in the 1970s, and they were later used in Central America during the 1980s. Argentina used extrajudicial killings as a way of crushing the liberal and communist opposition to the military junta during the "Dirty War" of the 1970s. For example, Alianza Anticomunista Argentina was a far-right death squad mainly active during the "Dirty War". The Chilean military regime of 1973–1990 also committed such killings.