By the late 1970s the insurgency had been reborn as a mostly Maya peoples rebellion organized around four Maoist-oriented rebel groups, mostly the Guerrilla Army of the Poor. In early 1982 the various guerrilla forces were inflicting 250 casualties per month on the army, so the military again resorted to destroy villages suspected of providing support to the rebels. By the late 1980s an estimated one million Guatemalans had been displaced within their own country and another 250,000 had fled to Mexico and settled in refugee camps there. In the 1980s Guatemala continued to acquire helicopters and airplanes to support the army. In 1981 Guatemala purchased at least 8 Bell 206B civilian helicopters as well as three Aérospatiale Alouettes, which they armed for combat. Four Fokker 27s light transport airplanes were acquired in 1982. Between 1975 and the early 1980s Israel supplied eleven Arava IAI-201 twin engine transport aircraft, which are excellent for small runways and were easily modified as a gunships with the addition of rocket pods and side-mounted machine guns. In the late 1980s France also supplied three Fouga CM.170 Magister jet trainer aircraft, which were also armed and used in combat. Air strikes were launched by A-37 jets and PC-7 armed trainers. One A-37 was lost in combat in 1988 down by ground fire in a close support operation.