Development of the 2K22 "Tunguska" was started by the command of the USSR State commission from
June 8 1970, and was intended to replace the ZSU-23-4 Shilka/Biryusa and the 9K33 Strela-1 (SA-9) / 9K35 Strela-10 (SA-13) systems with a common platform, capable of surviving the then new A-10A Thunderbolt, and US Army helicopters firing anti-armour missiles, such as the TOW equipped AH-1S and Hellfire equipped AH-64A Apache.
Tunguska was designed with a minimum range of 8km...
... Shilka facing ATGM: