The Peruvian Army was the main protagonist of the "Gobierno Revolucionario de las Fuerzas Armadas" (Revolutionary Government of the Armed Forces), an institutionalized military government that ruled the country between 1968 and 1980. During this period, defense expenditures underwent exponential growth allowing a rapid expansion of the Armed Forces and an unprecedented level of weapon acquisitions. In the early 1970s, US influence over the Army was replaced by a massive influx of Soviet training and equipment, including T-55 tanks, the BM-21 Grad, AK series rifles and the BTR series APCs plus a new Soviet-styled national military strategy of regaining the lost southern provinces which were now part of Chile. Political power returned to the civilians in the 1980s, but the rise of the terrorist insurgent group "Sendero Luminoso" (Shining Path) prompted the deployment of several Army units in a counter-insurgency role. Human rights violations associated with this intervention and a sharp decrease in the defense budget due to a general economic crisis caused serious problems for the Army morale and readiness as well as a strain on civil-military relations.