Operation Sana () was the final military offensive of the Army of the Republic of Bosnia and Herzegovina (Armija Republike Bosne i Hercegovine – ARBiH) in western Bosnia and Herzegovina and the last major battle of the Bosnian War. It was launched from the area of Bihać on 13 September 1995, against the Army of Republika Srpska (Vojska Republike Srpske – VRS), and involved advances towards Bosanski Petrovac, Sanski Most and Bosanska Krupa. At the same time, the Croatian Army (Hrvatska vojska – HV) and the Croatian Defence Council (Hrvatsko vijeće obrane – HVO) were engaging the VRS in Operation Mistral 2 further to the southeast. After an initial advance, VRS reinforcements managed to stop the ARBiH short of Sanski Most and Bosanski Novi, and reversed some of the ARBiH's territorial gains in a counterattack. After a part of the ARBiH 5th Corps was threatened with defeat around the town of Ključ, the ARBiH requested assistance from the HV.
The HV and HVO launched Operation Southern Move in response, removing the VRS pressure from Ključ and allowing the 5th Corps, reinforced by the 7th Corps, to resume its advance and capture Sanski Most on 12 October, by which time a comprehensive ceasefire was to come into effect throughout the country. Combat continued for another eight days without significant changes to the frontlines. Fighting did not resume, and the war ended the following month following negotiation and acceptance of the Dayton Agreement.
The operation commenced during a NATO bombing campaign against the VRS, codenamed Operation Deliberate Force, which targeted Bosnian Serb air defences, artillery and storage facilities initially in the area of Sarajevo, but also elsewhere in the country. Operation Sana, alongside concurrent HV and HVO offensives, sparked debate among military analysts as to whether the ground assaults or NATO's airstrikes were more responsible for ending the Bosnian War. Also in question was to what extent the advances of the ARBiH, HVO and HV were assisted by the airstrikes, and conversely, to what extent they hampered the VRS.
Background 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 re-organisation followed the declaration of the Serbian Republic of Bosnia and Herzegovina on 9 January 1992, ahead of the referendum on the independence of Bosnia and Herzegovina that took place between 29 February and 1 March 1992. 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 1992. 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, resulting in a cross-border operation by the Croatian Army (Hrvatska vojska – HV) 108th Brigade. On 4 April 1992, JNA artillery began shelling Sarajevo. There were other examples of the JNA directly supporting the VRS, such as during the capture of Zvornik in early April 1992, when the JNA provided artillery support from Serbia, firing across the Drina River. At the same time, the JNA attempted to defuse the situation and arrange negotiations elsewhere in the country.
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. In late April, the VRS was able to deploy 200,000 troops, hundreds of tanks, armoured personnel carriers (APCs) and artillery pieces. The HVO and the Croatian Defence Forces (Hrvatske obrambene snage – HOS) could field approximately 25,000 soldiers and a handful of heavy weapons, while the ARBiH was largely unprepared with nearly 100,000 troops, small arms for less than a half of their number and virtually no heavy weapons. Arming of the various forces was hampered by a United Nations (UN) arms embargo introduced in September 1991. 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 extent of the control was extended to about 70 percent of the country by the end of the year.
Prelude By 1995, the ARBiH and the HVO had developed into better-organised forces employing comparably large numbers of artillery pieces and good defensive fortifications. The VRS was not capable of penetrating their defences even where its forces employed sound military tactics, for instance in the Battle of Orašje in May and June 1995. In August 1995, after the fall of most of the Croatian Serb-controlled areas of Croatia during Operation Storm, the HV shifted its focus to western Bosnia. The shift was motivated by the desire to create a security zone along the Croatian border, establish Croatia as a regional power and gain favours with the West by forcing an end to the Bosnian War. The government of Bosnia and Herzegovina welcomed the move as it contributed to their goal of securing western Bosnia, as well as the largest Bosnian Serb-held city, Banja Luka.
In the final days of August 1995, NATO launched an air campaign targeting the VRS, codenamed Operation Deliberate Force. It was launched in response to the second Markale massacre of 28 August, which came on the heels of the Srebrenica massacre. Airstrikes began on 30 August, initially targeting VRS air defences, and striking targets near Sarajevo. The campaign was briefly suspended on 1 September and its scope was expanded to target artillery and storage facilities around the city. The bombing resumed on 5 September, and its scope extended to VRS air defences near Banja Luka by 9 September as NATO had nearly exhausted its list of targets near Sarajevo. On 13 September, the Bosnian Serbs accepted NATO's demand for the establishment of an exclusion zone around Sarajevo and the campaign ceased.
As the NATO bombing generally targeted VRS around Sarajevo, western Bosnia remained relatively calm following Operation Storm, except for probing attacks launched by the VRS, HVO or ARBiH near Bihać, Drvar and Glamoč. At the time the HV, HVO and ARBiH were planning a joint offensive in the region. The HV and HVO component of the offensive, codenamed Operation Mistral 2, was launched on 8 September with the aim of capturing the towns of Jajce, Šipovo and Drvar, while the ARBiH 7th Corps advanced on the right flank of the HV and the HVO towards Donji Vakuf. All four towns had been seized by 14 September, and the 7th Corps began transferring a substantial portion of its troops to the ARBiH 5th Corps in the Bihać area.
Order of battle The 15,000-strong ARBiH 5th Corps, commanded by Divisional General Atif Dudaković, was assigned the primary objectives, the capture of Bosanska Krupa, Bosanski Petrovac, Ključ and Sanski Most. Dudaković divided his eight brigades into two operational groups (OGs). OG (South), which comprised the 501st Mountain, 502nd Mountain, 510th Liberation and 517th Light Brigades, augmented by elements of the 5th Military Police Battalion, was commanded by Dudaković himself. OG (North), consisting of the 503rd Mountain, 505th Mountain, 506th Liberation and 511th Mountain Brigades, was commanded by his chief of staff, Brigadier Mirsad Selmanović. At the commencement of the operation, HV artillery provided fire support to OG South.
The 2nd Krajina Corps, commanded by Major General Radivoje Tomanić, and the 30th Infantry Division of the 1st Krajina Corps, commanded by Major General Momir Zec, were the VRS formations in the area. Tomanić, who set up his headquarters in Drvar, was in overall command in western Bosnia. Tomanić and Zec commanded a combined force of approximately 22,000 troops. The need to defend against both ARBiH corps and the combined HV and HVO force meant that the VRS had only 8,000 troops facing the 5th Corps. They were organised in six infantry or light infantry brigades stationed on the Grabež Plateau and near Bosanska Krupa and Otoka.
+Initial ARBiH order of battle Group Unit Notes South 501st Mountain Brigade Under command of Lieutenant General Atif Dudaković; Only some elements of the 5th Military Police Battalion were deployed; The assault against the VRS at the Grabež Plateau was supported by the Croatian Army artillery 502nd Knightly Mountain Brigade 510th Liberation Brigade 517th Light Brigade 5th Military Police Battalion North 503rd Mountain Brigade Under command of Brigadier Mirsad Selmanović 505th Knightly Motorised Brigade 506th Liberation Brigade 511th Mountain Brigade
+Initial VRS order of battle Area Unit Notes Grabež Plateau 15th Bihać Infantry Brigade 17th Ključ Infantry Brigade reinforced with a battalion of the 6th Sanska Infantry Brigade 3rd Petrovac Infantry Brigade 1st Serbian Infantry Brigade likely deployed, but unconfirmed Bosanska Krupa and Otoka 11th Krupa Light Infantry Brigade 1st Novi Grad Infantry Brigade
Timeline
First stage On 13 September, the ARBiH launched its advance, codenamed Sana 95, from Bihać towards the Sana River. The initial advance was undertaken by OG South and spearheaded by the 502nd Mountain Brigade against VRS positions on the Grabež Plateau south of the town. As its defences yielded to the ground assault supported by HV artillery fire, the VRS started to retreat south towards Bosanski Petrovac, alongside civilians fleeing the area. The ARBiH pursued the retreating VRS, capturing Kulen Vakuf the next day, and Bosanski Petrovac on 15 September. That same day, the ARBiH linked up with the HV approximately southeast of Bosanski Petrovac. The HV had captured Drvar and reached the Oštrelj Pass, as part of Operation Mistral 2. Both forces mistook the other for the VRS, leading to a friendly fire incident.
Even though the left flank of the salient created by the ARBiH advance was vulnerable, the VRS could not exploit the opportunity because it had no reserves available in the area. An effort to widen the salient commenced on 15 September, when OG North moved against Bosanska Krupa and Otoka in an assault spearheaded by the 503rd, 505th and 517th brigades. At the same time, OG South regrouped in Bosanski Petrovac in anticipation of reinforcements arriving from the 7th Corps. The regrouping involved the creation of a new formation, OG Centre, consisting of the 502nd, 505th, 506th and 517th brigades, all of which had been previously assigned to the two existing OGs. OG South's 501st and 510th brigades continued their advance, and captured Ključ on 17 September, having advanced covering since the start of the operation. On the same day, OG North captured Bosanska Krupa and Otoka, and the 510th Brigade was also transferred to OG Centre. This marked the completion of the first stage of Operation Sana.
OG Centre began its advance towards Sanski Most against the 1st Drvar and 1st, 2nd and 3rd Drina infantry brigades, which were remnants of the VRS units which had pulled out of Drvar at the end of Operation Mistral 2. OG North moved against Novi Grad as well as towards Sanski Most on the left flank of OG Centre, against opposition from the 1st Novigrad and 11th Krupa brigades and the former Drvar garrison. OG South, stripped of all its units except the 501st Brigade, and the 17th Krajina Mountain Brigade which had been transferred from 7th Corps, was tasked with capturing Mrkonjić Grad on the right flank of OG Centre.