Operation Rösselsprung () was a combined airborne and ground assault by the German XV Mountain Corps and collaborationist forces on the Supreme Headquarters of the Yugoslav Partisans in the Bosnian town of Drvar in the Independent State of Croatia during World War II. It was launched 25 May 1944, with the goal of capturing or killing Partisan leader Marshal Josip Broz Tito and destroying the headquarters, support facilities and co-located Allied military missions. It is associated with the Seventh Enemy Offensive () in Yugoslav history, forming part of the Seven Enemy Offensives historiographical framework. The airborne assault itself is also known as the Raid on Drvar ().

Operation Rösselsprung was a coup de main operation, involving direct action by a combined parachute and glider-borne assault by the 500th SS Parachute Battalion and a planned subsequent link-up with ground forces of the XV Mountain Corps converging on Drvar. The airborne assault was preceded by heavy bombing of the town by the Luftwaffe. The ground forces included Home Guard forces of the Independent State of Croatia along with collaborationist Chetniks. Tito, his principal headquarters staff and the Allied military personnel escaped, despite their presence in Drvar at the time of the airborne assault. Fierce Partisan resistance in the town itself and along the approaches to Drvar contributed to the failure of the mission. Other factors included the German intelligence agencies refusing to share the limited information available on Tito's exact location, and the lack of contingency planning by the commander of the German airborne force.

Background

On 6 April 1941 the Axis powers invaded Yugoslavia from multiple directions, rapidly overwhelming the under-prepared Royal Yugoslav Army which capitulated 11 days later. In the aftermath of the invasion Yugoslavia was partitioned between the Axis powers through a combination of annexations and occupation zones. An Axis puppet state known as the Independent State of Croatia (, NDH) was established on the territory of modern-day Croatia and Bosnia and Herzegovina, controlled by the fascist and ultra-nationalist Ustaše. The NDH was divided by a German–Italian demarcation line, known as the "Vienna Line"; the Germans occupied the north and northeastern parts of the NDH, and the Italians the south and southwestern sections. The NDH immediately implemented genocidal policies against the Serb, Jewish, and Romani population of the puppet state.

Following the collapse of Yugoslavia, armed groups appeared, and in the territory of the NDH, while the predominantly Serb resistance to Ustaše rule was initially not strongly aligned with ideology, two principal groups soon established themselves, the communist-led Partisans and the Serb nationalist Chetniks. The Partisans were resolutely anti-Axis throughout the war, but the Chetniks extensively collaborated with Italian occupation forces garrisoned in the NDH from mid-1941, and also with the Germans, especially after the Italian capitulation in September 1943.

The Axis Operation Weiss and Operation Schwarz offensives of the first six months of 1943 caused significant setbacks for the Partisans; however, in September the Partisan leader Josip Broz Tito took advantage of the capitulation of Italy and managed to increase the territory under his control and double his forces to around 200,000 men, arming them with captured Italian weapons. In late November, he held a National Congress at Jajce in a liberated area of the NDH, during which he was designated marshal of Yugoslavia and prime minister. He established his headquarters nearby at Drvar in the Dinaric Alps and temporarily suspended his successful tactic of being constantly on the move. Maximilian von Weichs, the Wehrmacht commander-in-chief for Southeast Europe, admitted a few weeks later that "Tito is our most dangerous enemy."

Tito's personal headquarters was initially located in a cave below a ridgeline about north of the centre of Drvar. Below the cave ran the Unac River, creating an obstacle to movement between the town and the cave, and a rail line ran along the ridgeline above the cave. As well as Partisan headquarters, several Partisan and Communist Party support, training and youth organisations were based in and around Drvar at the time, along with the Tito Escort Battalion which was responsible for Tito's personal safety. The British and Soviet military missions to the Partisans were also stationed in villages close to Drvar, as were some United States military officers. The British mission was headed by Brigadier Fitzroy Maclean, who was in London at the time of the raid, and included Major Randolph Churchill, son of Winston Churchill. At the time of Operation Rösselsprung (), the British mission was led by its second-in-command, Lieutenant Colonel Vivian Street.

Partisan dispositions around Drvar

Apart from Partisan headquarters and related organisations in and around Drvar, there were between 12,000 and 16,000 Partisans in the area of operations that would be subject to the ground assault by XV Mountain Corps. Near Drvar were elements of the 1st Proletarian Corps commanded by Koča Popović; this corps consisted of the elite 1st Proletarian and 6th Lika Proletarian divisions, the corps headquarters being located in the village of Mokronoge, east of Drvar. Its subordinate formations were further away, the 6th Lika Proletarian Division west of Drvar, and the 1st Proletarian Division deployed in the area around Jajce and Mrkonjić Grad, some east of Drvar. The nearest large Partisan formation to Drvar was the 3rd Lika Proletarian Brigade of the 6th Lika Proletarian Division based in the Resanovci and Trubar villages some south and southwest of Drvar.

In the wider area of operations were the Partisan 5th Corps commanded by Slavko Rodić and the 8th Corps commanded by Vlado Ćetković. The 5th Corps was deployed to the northeast and northwest of Drvar with its headquarters south of the Mrkonjić Grad–Ključ road, and the 8th Corps was positioned to the southeast with its headquarters in the mountains between the Glamoč and Livno valleys. Importantly for the coming battle, the 4th Krajina Division of the 5th Corps was deployed between Bihać and Bosanski Petrovac. Two brigades of the 4th Krajina Division and one brigade from the 39th Krajina Division formed a defensive arc north of Drvar, running from Bihać through Krupa to Sanski Most. The 9th Dalmatian Division of the 8th Corps was deployed to the south between Livno and Bosansko Grahovo.

German intelligence

Three German intelligence organisations attempted to determine the location of Tito's headquarters and the disposition of Partisan forces in Drvar. The first of these was the Benesch Special Unit of Section II of the (the Wehrmacht intelligence service), some members of which had been involved in identifying Tito's presence in the town of Jajce prior to the German offensive to retake the town. The Benesch Special Unit was part of the Brandenburg Division, and was staffed by ethnic Germans who spoke local languages. The unit had many contacts with both the Chetniks and the Ustaše Militia, and had been tracking Tito since October 1943. Kirchner of that unit had been responsible for locating Tito before the re-capture of Jajce, and he established a patrol base near Bosansko Grahovo. He got very close to the Drvar cave, and located the Allied military missions, but despite German radio intercepts confirming that Drvar was the site of Tito's headquarters, Kirchner was unable to pinpoint the cave as the location of the headquarters. Kirchner was attached to the 500th SS Parachute Battalion for the operation.

The second intelligence organisation was FAT (Front Reconnaissance Troop) 216 of Section I of the . FAT216, commanded by Zavadil, was also attached to the 500th SS Parachute Battalion, but did not contribute much to the intelligence used to plan the raid.

On Adolf Hitler's orders, Otto Skorzeny of the (SD, the intelligence branch of the SS), who had commanded the operation to rescue Mussolini in September 1943, was independently involved in intelligence gathering in the lead-up to the raid. Skorzeny acted on behalf of the SD, and after obtaining information from a Partisan deserter that pinpointed Tito's headquarters at the cave, he proposed a plan to infiltrate Drvar with a small group of soldiers to assassinate Tito. Skorzeny soon discovered that the plan to eliminate Tito had been compromised, and had nothing further to do with the operation. It appears that he did not pass on the useful intelligence he had gathered to Kurt Rybka, the commander of the 500th SS Parachute Battalion, who was responsible for planning the critical airborne aspects of the operation. Largely due to interservice rivalry and competition, the three organisations did not share the intelligence they gathered, which had a significant effect on the tactical planning and execution of the operation. The Germans found forged documents that stated 25 May was Tito's birthday and therefore planned the attack for that day.

Partisan intelligence

The Partisans had an effective intelligence network. They had been aware of the presence of the 500th SS Parachute Battalion in Yugoslavia for some time, and of the general threat of an airborne assault for over six months. They may have become aware of the isolation of the 500th SS Parachute Battalion or the concentration of transport aircraft and gliders at Zagreb and Banja Luka over a month before the operation. The Partisans also managed to capture the deserter that Skorzeny had interrogated. As a result of these early indicators of an attack, Tito's main headquarters was relocated to another cave near the village of Bastasi, west of Drvar. Tito then used the Drvar cave during the day, but returned to the Bastasi cave at night. As a further precaution, elements of the 6th Lika Proletarian Division were moved closer to Drvar.

On 23 May 1944, a single German Fieseler Fi 156 reconnaissance aircraft flew several parallel runs up and down the Una valley over Drvar at around ; activity consistent with conducting aerial photography. The aircraft paid particular attention to the villages of Prinavor and Trninić Brijeg where the British military mission and American military personnel were located. This was observed by Street, the acting commander of the British military mission, who assumed it was spotting for a bombing raid and advised both Tito and the Americans. Both Allied missions moved their locations as a result.

Despite the intelligence received and observations made by the British, the Partisans appear to have been quite complacent about the threat; Tito's chief of staff, Arso Jovanović, swore that "a German attack was impossible". The most obvious indicator that Tito was unaware of the imminent attack is that he remained at the Drvar cave overnight on the evening of 24 May, following a celebration, instead of returning to Bastasi.

Through Ultra intercepts of German signal traffic, the British had become aware that the Germans were planning an operation codenamed "Rösselsprung". However, the information available did not include where the operation would occur or what its objectives might be.

Planning