In 1978, a coup by left-wing army officers overthrew the Afghan government. With Soviet support, a coalition of Communist factions assumed power and began a sweeping programme of land reform, fiercely opposed by the devoutly Muslim majority of the population. Tribal mujahideen (fighters for jihad) rebelled across the country, and, with the government nearing collapse, the Soviet Union decided on military intervention to prop up its client. Despite overwhelming superiority in military hardware, the tenacity of the opposition and the formidable terrain defeated Soviet efforts to take control outside the main urban centres. As the war wore on, surreptitious military support from the USA and Saudi Arabia tilted the balance in favour of the insurgents, particularly the introduction of hand-held anti-aircraft weaponry. The capture of the rebel stronghold in Zhawar (1986) was a rare success: it was soon retaken. By 1988, the Soviet Union itself was beginning to disintegrate, and a humiliating withdrawal was ordered.