The Mexican Dirty War was the Mexican theater of the Cold War, an internal conflict from the 1960s to the 1980s between the Mexican Institutional Revolutionary Party (PRI)-ruled government under the presidencies of Gustavo Díaz Ordaz, Luis Echeverría, and José López Portillo, which were backed by the U.S. government, and left-wing student and guerrilla groups. During the war, government forces carried out systematic torture, "probable extrajudicial executions", and an estimated 1,200 disappearances.