Entering service at the peak of the Cold War, the MiG-21 quickly replaced the US-supplied North American F-86E and F-86D Sabres in the Yugoslav inventory. The first version, MiG-21F-13, was followed by the MiG-21PFM in 1967, and MiG-21M/MF in 1970. Serving with the 204th Fighter Regiment, the task of these fighters was the air defence of Belgrade, capital of Yugoslavia. In Tito's Yugoslavia, the MiG-21 was also deployed for strategic reconnaissance. In 1968-1969, the JRV i PVO introduced the MiG-21R to service, which became the primary photo and electronic reconnaissance platform of the entire military. The importance of the fleet was further increased in 1984, when US-made Fairchild KA-112 LORAP containers were added to their arsenal. The final and most widely used version became the MiG-21bis, delivered to Yugoslavia in the 1977-1983 period. By the time of the dissolution of the country, in 1991-1992, it formed the backbone of the fleet and saw intensive combat service as a fighter-bomber during the conflicts in Slovenia, Croatia, and Bosnia and Herzegovina. Of particular interest during this period was the widespread use of diverse ordnance of native and NATO-origins. While operated by the RV i PVO, MiG-21s did not fly any combat sorties during NATO's campaign against the Federal Republic of Yugoslavia of 1999 - better known as the 'Kosovo War'. Nevertheless, it was intensively targeted by NATO's air power, resulting in destruction of nearly half the fleet. Although subsequently considered 'obsolete', and operated in continuously declining numbers, the MiG-21bis continued soldiering on with the RV i PVO, and even maintained quick reaction alert duty until late 2015, when officially retired.