ZU stands for Zenitnaya Ustanovka (Russian: Зенитная Установка) – anti-aircraft mount.

It was designed to engage low-flying targets at a range of 2.5 km as well as armoured vehicles at a range of two kilometres and for direct defence of troops and strategic locations against air assault usually conducted by helicopters and low-flying airplanes.

ZU-23-2 can be identified by different placement of the ammunition boxes (at right angles to the gun carriage) and by muzzle flash suppressors.

From 1965 onwards, the Soviet Union began supplying the Democratic Republic of Vietnam with large shipments of weapons.

[18] During the Soviet–Afghan War, the Soviet forces placed ZU-23-2 sets in the occupied areas to secure their positions, employing them in both the static defense and direct fire support roles.

In the later Afghan Civil War, the main belligerents, the Taliban and the Northern Alliance forces also employed ZU-23-2 autocannons mounted on BMP-1 and BTR-70 APCs or GAZ-66 and ZIL-131 trucks, along with SA-7 Grail or Stinger Missiles, as their primary air-defense and direct fire support weapons.

[19] They proved very useful in urban combat, being employed in the direct fire support role by the Syrian Army, the Palestine Liberation Organization (PLO) guerrilla factions and the various Christian and Muslim Lebanese militias.

[20] In late 1983, the ZU-23-2 was used on attacks against dug-in positions held by U.S. Marine ground units serving with the Multinational Force in Lebanon (MNF II).

[21] During the Gulf War of 1991, it was a favorite weapon of the Iraqi Army, albeit used more often against ground targets such as infantry and light enemy vehicles.

The confusion arose from the fact the airplane was approaching from the west, instead of the usual easterly landing direction, and overflew the airfield at a low altitude due to animals on or in the vicinity of the runway.

Ethiopian soldiers interpreted these facts as indicative of a suicide plane looking to strike targets within the base camp, and responded with fire.