 Yugoslav Air force units that operated MiG-21 were the 204th Fighter-Aviation Regiment at Batajnica Air Base (126th, 127th and 128th fighter-aviation squadrons), 117th fighter-aviation regiment at Željava Air Base (124th and 125th fighter-aviation squadron and 352nd recon squadron), 83rd fighter-aviation regiment at Slatina Air Base (123rd and 130th fighter aviation squadron), 185th fighter-bomber-aviation squadron (129th fighter-aviation squadron) at Pula and 129th training center at Batajnica air base.During the early stages of the 1990s' Yugoslav wars the Yugoslav military used MiG-21s in a ground-attack role, while Croatian and Slovene forces did not have air forces at the beginning of the war.Aircraft from air bases in Slovenia, Croatia, and Bosnia and Herzegovina were relocated to air bases in Serbia.