Operation Corridor 92

Operation Corridor 92 (Serbo-Croatian: Операција Коридор 92, Operacija Koridor 92) was the largest operation conducted during the Bosnian war by the Army of Republika Srpska (VRS) against the forces of the Croatian Defence Council (HVO) and the Croatian Army (HV) in the Bosanska Posavina region of northern Bosnia and Herzegovina between 24 June and 6 October 1992. The objective of the offensive was to re-establish a road link between the city of Banja Luka in the west of the country and the eastern parts of the territory controlled by the Bosnian Serbs. The offensive was prompted by the capture of Derventa by the HV and the HVO – a move that blocked the single overland road between the VRS-controlled territories.

The VRS successfully captured Derventa and pushed the HVO and the HV north, capturing several towns in the process. In the second phase of the offensive, the VRS reached the Sava River, the border with Croatia, and destroyed a bridgehead held by the HV and the HVO at Bosanski Brod. The offensive involved more than 60,000 troops and resulted in heavy casualties for all sides, especially the HVO. The Croatian National Defence Council commissioned a report into the loss of Bosanska Posavina and blamed internal conflicts, a double chain of command and ineffective counterintelligence for the defeat. The outcome later caused speculation that it was the result of a political arrangement between Serb and Croatian leaders to secure a land trade, though a Central Intelligence Agency analysis rejected such allegations.

As the Yugoslav People's Army (Jugoslovenska narodna armija – JNA) withdrew from Croatia following the acceptance and start of implementation of the Vance plan, its 55,000 officers and soldiers born in Bosnia and Herzegovina were transferred to a new Bosnian Serb army, which was later renamed the Army of Republika Srpska (Vojska Republike Srpske – VRS). This reorganisation followed the declaration of the Serbian Republic of Bosnia and Herzegovina on 9 January 1992, ahead of the 29 February – 1 March 1992 referendum on the independence of Bosnia and Herzegovina. This declaration would later be cited by the Bosnian Serbs as a pretext for the Bosnian War. Bosnian Serbs began fortifying the capital, Sarajevo, and other areas on 1 March. On the following day, the first fatalities of the war were recorded in Sarajevo and Doboj. In the final days of March, Bosnian Serb forces bombarded Bosanski Brod with artillery, drawing a border crossing by the HV 108th Brigade in response. On 4 April, JNA artillery began shelling Sarajevo.

The JNA and the VRS in Bosnia and Herzegovina faced the Army of the Republic of Bosnia and Herzegovina (Armija Republike Bosne i Hercegovine – ARBiH) and the Croatian Defence Council (Hrvatsko vijeće obrane – HVO), reporting to the Bosniak-dominated central government and the Bosnian Croat leadership respectively, as well as the HV, which occasionally supported HVO operations. A UN arms embargo introduced in September 1991, had hampered the preparation of the various forces, but in late April, the VRS was able to deploy 200,000 troops, along with hundreds of tanks, armoured personnel carriers (APCs) and artillery pieces, while the HVO and the Croatian Defence Forces (Hrvatske obrambene snage – HOS) could field approximately 25,000 soldiers and a handful of heavy weapons. The ARBiH was largely unprepared, however, lacking heavy weapons and possessing small arms for less than half of its force of approximately 100,000 troops. By mid-May 1992, when those JNA units which had not been transferred to the VRS withdrew from Bosnia and Herzegovina to the newly declared Federal Republic of Yugoslavia, the VRS controlled approximately 60 percent of Bosnia and Herzegovina.

The geographic area in the basin of the Sava River consisted in part or entirely of 15 municipalities: Bosanska Dubica, Bosanska Gradiška, Srbac, Bosanski Brod, Derventa, Odžak, Modriča, Gradačac, Bosanski Šamac, Orašje, Brčko, Srebrenik, Bijeljina, Lopare, and Ugljevik. Since the 1990s, the use of the term Bosanska Posavina relates almost exclusively for predominantly Croat inhabited areas within the municipalities of Bosanski Brod, Derventa, Odžak, Modriča, Gradačac, Bosanski Šamac, Orašje and Brčko. These municipalities had an area of 2,289.15 square kilometres (883.85 mi²) and were in 1991 inhabited by 319,593 people, of which 133,467 (41.76%) were Croats, 70,907 (22.19%) were Bosniaks, and 88,484 (27.69%) were Serbs. The region was connected with Croatia by four bridges on the Sava River.

Following the 1990 parliamentary election, the Croatian Democratic Union (HDZ) had a majority in six municipalities of Bosanska Posavina. However, the political situation in the region, especially by the end of 1991, was marked with obstructions by the Serb Democratic Party (SDS) that established parallel authorities. Throughout 1991, the SDS established six autonomous regions (SAOs) in Serb-inhabited municipalities of Bosnia and Herzegovina. The SAO Northern Bosnia, proclaimed in Doboj in November, covered 17 municipalities, including Derventa, Bosanski Brod, Odžak, Bosanski Šamac, Modriča, Gradačac and Orašje. These SAOs were joined into Republika Srpska on 9 January 1992.

On 12 November 1991, the Croatian Community of Bosnian Posavina was established in Bosanski Brod. It covered eight municipalities: Bosanski Brod, Odžak, Bosanski Šamac, Orašje, Derventa, Modriča, Gradačac and Brčko.

Following its successful defence of Bosanski Brod in March, the HVO, reinforced by HV troops, pushed the JNA and the VRS south from the town and captured the towns of Modriča and Derventa by the end of May. The capture of Derventa also severed the last road available to the Bosnian Serbs spanning VRS-controlled western Bosnia around Banja Luka and the VRS-held territory in the east of the country, adjacent to Serbia. That prevented the supply of Banja Luka as well as the bulk of the territory gained by the Republic of Serbian Krajina (RSK) and Croatian Serbs in Croatia since the initial phase of the Croatian War of Independence.