The Soviet invasion of Afghanistan was initiated on December 25, 1979, when Soviet airborne troops began to land in Kabul, proceeding to take government and military buildings and destroying major communication centers. On December 27, Soviet ground forces, led by Sergei Sokolov, invaded Afghanistan from the north. Afghan president Hafizullah Amin was assassinated on the same day. The Russian occupation of Afghanistan lasted until February 1989, when the Soviet Union, under Gorbachev, withdrew the troops from this country, following the Geneva Accords that had been signed the year before. During this period, there was a ferocious war between the Soviet troops and Islamic guerrilla fighters, known as the Mujahideen, who received undercover military aid from Pakistan and the US government. The Russian forces that participated in the invasion of Afghanistan were the 103rd Guards Airborne Division, 56th Separate Airborne Brigade, 5th and 108th Guards Motor Rifle Divisions; this invading force included 1,800 tanks, about 2,100 armored fighting vehicles, and 350 attack and transport helicopters.
The root cause of the Soviet invasion lies in the ideological and political alignment of Afghanistan with the Soviet Union carried out in 1978, under the Afghan communist government. That year, the center-right government of Mohammad Khan, had been ousted by Marxist army officers, commanded by Nur Taraki. The following year, Taraki signed a treaty with Leonid Brezhnev and Andrei Gromyko, by which the Soviet Union would give him military support by deploying two army divisions on the Soviet-Afghan border. This leftist government undertook radical reforms, such as universal secular (nonreligious) education, and equal rights to women. These measures were extremely unpopular for the Muslim population and religious leaders, triggering violent revolts among Afghan tribes. By mid 1979, Hafizullah Amin, another Marxist leader, took over the Afghan government as Taraki was assassinated during a power struggle. This new communist government became even more unpopular; as a result, Amin attempted to establish diplomatic links with Pakistan and China as he purged pro-Soviet Afghan officials.