Faced with opposition to his reform efforts, Fujimori dissolved Congress in the "auto-golpe" ("self-coup") of 5 April 1992. He then revised the constitution; called new congressional elections; and implemented substantial economic reform, including privatization of numerous state-owned companies, creation of an investment-friendly climate, and sound management of the economy. Fujimori's administration was dogged by insurgent groups, most notably the Sendero Luminoso, who carried out terrorist campaigns across the country throughout the 1980s and 1990s. Fujimori cracked down on the insurgents and was successful in largely quelling them by the late 1990s, but the fight was marred by atrocities committed by both the Peruvian security forces and the insurgents: the Barrios Altos massacre and La Cantuta massacre by Government paramilitary groups, and the bombings of Tarata and Frecuencia Latina by Sendero Luminoso. Those incidents subsequently came to symbolize the human rights violations committed in the last years of violence.