Operation Primicia ("Scoop") was a large guerrilla assault that took place on 5 October 1975, in Formosa, Argentina. It was the largest attack ever launched by the paramilitary group Montoneros, which attempted to seize the barracks of the 29th Forest Infantry Regiment. The incident worsened the Dirty War, and indirectly led to the 1976 Argentine coup d'état the following year.