The Massacre of Margarita Belén took place during the Dirty War in Argentina. It involved the torture and execution of 22 Montoneros, some of whom were killed after surrendering and laying down their weapons near the town of Margarita Belén, Chaco Province, on 13 December 1976, in a joint operation of the Argentine Army and the Chaco Provincial Police. One of the victims of the massacre, Néstor Carlos Salas, is reported to have been a Montoneros commander and took part in a number of guerrilla operations.