The Yugoslav People's Army (JNA/ЈНА; Macedonian, Montenegrin and Serbian: Југословенска народна армија, Jugoslovenska narodna armija; Croatian and Bosnian: Jugoslavenska narodna armija; Slovene: Jugoslovanska ljudska armada, JLA), also called the Yugoslav National Army,[1][2] was the military of the Socialist Federal Republic of Yugoslavia and its antecedents from 1945 to 1992.

A Military Assistance Advisory Group (MAAG) of 30 officers commanded by Brigadier General John W. Harmony[10] was established by the United States in Belgrade in 1951.

The main task of the Yugoslav People's Army was to protect the independence, sovereignty, territorial integrity and social organization of the Socialist Federal Republic of Yugoslavia.

[14] The Secretary of Defence was the officer with the highest military rank that could command the armed forces, including the Yugoslav People's Army and Territorial Defense.

[14] The Chief of Staff of the Yugoslav People's Army, in the case that the Secretary of Defense was prevented or absent to fulfill his function, was formally his deputy who could take command of the armed forces.

Under reforms through the "Jedinstvo" plan it was planned to reorganize the army's structure into four major army areas called "Vojna Oblast" under command of the Federal Secretariat of People's Defence (SSNO) – "Vojna oblast" or military regions were further divided into corps, brigades, garrisons and smaller districts and sectors that were responsible for administrative tasks such as draft registration, mobilization, and construction and maintenance of military facilities.

In the "Jedinstvo 1" reforms, JNA eliminated most of its old divisional infantry organization and established the brigade and corps structure with some independent units under direct command of SSNO.

The shift to brigade-level organization provided greater operational flexibility, maneuverability, and tactical initiative and reduced the possibility that large army units would be destroyed in set piece engagements with an aggressor.

To the military leadership of the JNA, it was obvious that USSR was moving to defend its internal borders and the only global superpower left was the USA.

[19] Under "Jedinstvo 2", the JNA on 1 January 1990 had:[19] and many others, including 19 military police battalions and river flotilla giving in total 28 divisions, 307 brigades and regiments and 137 independent battalions/divisions.

The air force also had about ninety armed Mi-8 helicopter gunships to provide added mobility and fire support for small ground units.

By 1989, Yugoslavia started developing a new domestic multirole fighter plane called Novi Avion, which was supposed to replace the MiG-21 and J-21 Jastreb fleets entirely.

Minor surface combatants operated by the Yugoslav Navy included nearly eighty frigates, corvettes, submarines, minesweepers, and missile, torpedo, and patrol boats in the Adriatic Fleet.

The Partisans had operated many small boats in raids harassing Italian convoys in the Adriatic Sea during World War II.

The navy's fifteen Topčider-class torpedo boats included four former Soviet Shershen class and eleven Yugoslav built units.

It is defined in article 242 of the constitution, which says that, "Regarding the composition of staff and the employment in the high command and leadership functions in the Yugoslav People's Army the principle is applied of as proportional representation as possible of republics and autonomous provinces".

[22] Nobody was preventing anyone in Yugoslavia to become JNA officer in accordance to the law "Zakon o vojnim školama i naučnoistraživačkim ustanovama Jugoslovenske narodne armije" that had no exclusions clause.

The TDF would supplement the YPA, giving it greater defensive depth and an armed local population ready to support combat actions.

It was believed by the Yugoslav planners to be the best method by which a smaller nation could properly defend itself against a much stronger invader, specifically, NATO or the Warsaw Pact.

In January 1990, the League of Communists of Yugoslavia was effectively dissolved as a national organization following its 14th Congress where the Serbian and Slovene delegations engaged in a public confrontation.

The dissolution of Yugoslavia began when independent, non-communist governments were established in the Yugoslav republics of Slovenia, Croatia, Bosnia and Herzegovina, and Macedonia.

In March 1991, Yugoslav defense minister General Veljko Kadijević organized a meeting at the military complex in Topčider, Belgrade.

"[32] He also stated that the Yugoslav People's Army was dealing with Ustaše, Chetniks, and other "enemies of socialism" stemming from World War II conflicts.

In April 1991, the government of Croatia formed the Croatian National Guard (ZNG), which the Yugoslav People's Army considered to be a paramilitary organization.

On the same day, Slovenian Territorial Defence units captured Yugoslav control posts on the borders with Italy, Hungary and Austria.

The Slovenian Territorial Defence blockaded all ten Yugoslav bases in Slovenia and kept them under siege in the Ten-Day War which ended on 6 July 1991.

Senior Yugoslav officers also defected to Croatia, including Air Force Commander-in-Chief Colonel general Anton Tus.

Many atrocities were committed in the city by the Yugoslav People's Army and local Serb guerrillas and regulars, including the Velepromet concentration camp, Vukovar massacre, etc.

Around the same time, Bosnia and Herzegovina declared independence following a referendum and the Bosnian War started soon thereafter between the country's Bosniaks, Croats and Serbs.

[42] Later renamed Republika Srpska,[43] it developed its own military as the JNA withdrew and handed over its weapons, equipment and 55,000 troops to the newly created Bosnian Serb army.