Kozara Offensive

The Kozara Offensive (Serbo-Croatian: Kozaračka ofenziva/ofanziva), also known as Operation West Bosnia (German: Operation West-Bosnien) was a large-scale German-led counter-insurgency operation against the Yugoslav Partisans in the Bosnian mountain region of Kozara in the Independent State of Croatia during World War II. It was launched on 10 June 1942, with the goal to encircle and destroy the Partisans who were operating in the Kozara mountain region near Banja Luka, which threatened German access to the Belgrade-Zagreb railway.

The offensive was a coup de main operation, which utilized direct action by elements of the Wehrmacht, Home Guard and Ustaše. Poorly equipped and outnumbered, the Partisans were nearly annihilated during the fight, with only a few hundred partisans narrowly escaping as the German-NDH forces recaptured the area, including the city of Prijedor. The Germans and their allies encircled the main group and achieved their objectives after nearly 40 days of bloody combat, with heavy casualties on both sides.

The Kozara Offensive became a part of national mythology in post-war Yugoslavia, which honored the bravery and martyrdom of the Partisans. It also earned a reputation as German and NDH forces massacred Serb civilians as the battle progressed. Most of the civilians were killed during or after the battle. Others were sent to concentration camps such as Jasenovac, Stara Gradiška, Sajmište, or forced labor mines in German occupied Norway, where many perished.

Yugoslavia was invaded by the Axis powers of Nazi Germany, Fascist Italy, Hungary and Bulgaria on 6 April 1941. On 17 April, the Yugoslav army surrendered after a short campaign. Afterwards, a pro-Axis puppet state in modern-day Croatia, Bosnia and Herzegovina and parts of Serbia called the Independent State of Croatia (Serbo-Croatian: Nezavisna Država Hrvatska or NDH) was established, led by dictator Ante Pavelić. His Ustaše militias became infamous for their sadistic actions against the Serb, Roma, and Jewish populations within the region. One of the policies the NDH had was to annihilate the Serb population through forced assimilation, deportations, and massacres.

Within the occupied Yugoslav territories and in the NDH, armed resistance broke out almost immediately as the Ustaše violence grew. While initial resistance lacked a centralized leadership and was not strictly aligned with any ideology, two main groups eventually grew in size and importance, the Serbian royalist Chetniks led by Draža Mihailović and the multi-ethnic communist Partisans led by Josip Broz Tito. Both groups initially collaborated against the Axis, however differing policies and moral codes eventually led to a guerrilla war between the two movements. While the Partisans were anti-Axis, the Chetniks began extensively collaborating with Italian, German and NDH forces around mid-1942.

In April 1942, the Partisans in northern Bosnia liberated Bosanski Petrovac, Drvar, Glamoč, and Prijedor. The Ustaše commander Vjekoslav Luburić sent out a plan for a "security belt" around the river Sava and gave orders to round up the Serb population that was seen as supportive of the Partisans. Upon realizing this, whole villages deserted to the Partisans divisions hiding in the mountain of Kozara. This was reported by the Ustaše on 8 April 1942, "Jablanac: the inhabitants of the Orthodox faith moved with all their possessions to Orahova village. The five Catholic families moved to the village of Mlaka.”

A military operation was planned beginning in May 1942 to eliminate any Partisan influence and round up the Serb population now seen as supportive of the communist Partisans. The Germans and NDH were concerned that their next move would be capturing Banja Luka which would disrupt German weapon transports in the Belgrade-Zagreb railway. The future Secretary General of the United Nations and President of Austria Kurt Waldheim was involved in the planning and implementation. His involvement and tenure in Yugoslavia during World War II would later draw international notoriety.

Kampfgruppe West-Bosnien had around 39,000 soldiers under the command of Generalleutnant Friedrich Stahl. The German Wehrmacht had 15,000 soldiers from the 704th and 714th Infantry Divisions, while the Ustaše and Home Guard engaged 22,000 alongside elements of the 1st Ustaše Regiment of the Black Legion. 2,000 Chetnik soldiers under the command of vojvoda Rade Radić would also participate in this battle. Radić previously fought alongside the Partisans but would later grow disillusioned with their ideology. In April 1942, he formed his own Chetnik division and staged a coup at a hospital near Banja Luka, killing several Partisans including physician Mladen Stojanović. The Partisans had only around 3,500 soldiers, consisting of men from the 2nd Krajina Detachment, with elements of the 3rd and 4th battalions of the 1st Detachment. Despite these setbacks, the men were well trained as many were foreign Republican veterans of the Spanish Civil War.