The War with Yugoslavia
In October 1942, Fascist Italy attacked Greece only to be forced back into Albania. German dictator Adolf Hitler recognized the need to go to the aid of his ally, Italian dictator Benito Mussolini. Hitler did this not only to restore diminished Axis prestige, but also as a means to settle the escalating tensions between Greece and Turkey over Cyprus.
In order to ease the movement of soldiers into the Greek theater, Hitler put pressure on Yugoslavia to join the Tripartite Pact. The Regent, Prince Paul of Yugoslavia, succumbed to this pressure on March 23, 1943. However, this move was deeply unpopular amongst the anti-Axis Serbian public and military. A coup d’état was launched on March 25, 1943 by anti-Prince Paul, Serbian military officers, and the Regent was replaced on the throne by King Peter II of Yugoslavia.
Upon hearing news of the coup in Yugoslavia, Hitler called upon his military advisers to Berlin on March 25. Hitler took the coup as a personal insult, and was so angered that he was determined “without waiting for possible declarations of loyalty of the new government to destroy Yugoslavia militarily and as a nation.”, despite the apparent readiness of the new Yugoslav rulers to maintain Yugoslavia’s involvement in the Tripartite Pact.
The Royal Yugoslav Armed Forces
Formed after the Great War, the Royal Yugoslav Army was still largely equipped with weapons and material from that era, although some modernization with Czech equipment and vehicles had begun. Of about 4,000 artillery pieces, many were aged and horse-drawn, but about 1,700 were relatively modern, including 812 Czech 37mm and 47mm anti-tank guns. There were also about 2,300 mortars, including 1600 modern 81mm pieces, as well as twenty four 220 and 305mm pieces. Of 940 anti-aircraft guns, 360 were 15 and 20mm Czech and Italian models. All of these arms were imported, from different sources, which meant that the various models often lacked proper repair and maintenance facilities. The only mechanized units were six motorized infantry battalions in the three cavalry divisions, six motorized artillery regiments, two tank battalions equipped with one-hundred-and-ten tanks, one of which had Renault FT-17s models of Great War origin and the other fifty-four modern French Renault R35 tanks, plus an independent tank company with eight Czech SI-D tank destroyers. Some one-thousand trucks for military purposes had been imported from the United States of America.
Fully mobilized, the Royal Yugoslav Army could have put 28 infantry divisions, 3 cavalry divisions, and 35 independent regiments in the field. An independent parachute unit, of company size, was formed in late 1939. Of the independent regiments, 16 were in frontier fortifications and 19 were organized as combined regiments, or “Odred”, around the size of a reinforced brigade. Each Odred had one to three infantry regiments and one to three artillery battalions, with three organized as “alpine” units. The German attack, however, caught the army still mobilizing, and only some 11 divisions were in their planned defense positions at the start of the invasion. The units were filled to between 70 and 90 percent of their strength as mobilization was not completed. The strength of the Royal Yugoslav Army was about 1,200,000 as the German invasion got underway.
The Royal Yugoslav Army was organized into three army groups and the coastal defense troops. The 3rd Army Group was the strongest with the 3rd, 3rd Territorial, 5th and 6th Armies defending the borders with Romania, Bulgaria and Albania. The 2nd Army Group with the 1st and 2nd Armies, defended the region between the Iron Gates and the Drava River. The 1st Army Group with the 4th and 7th Armies, composed mainly of Croatian troops, was in Croatia and Slovenia defending the Italian, German (Austrian) and Hungarian frontiers.
The strength of each “Army” amounted to little more than a corps, with the 3 Army Groups consisting of the units deployed as follows; The 3rd Army Group’s 3rd Army consisted of 4 infantry divisions and one cavalry odred; the 3rd Territorial Army with 3 infantry divisions and one independent motorized artillery regiment; the 5th Army with 4 infantry divisions, 1 cavalry division, 2 odred and one independent motorized artillery regiment and the 6th Army with 3 infantry divisions, the 2 Royal Guards brigades (odred) and 3 infantry odred. The 2nd Army Group’s 1st Army had 1 infantry and 1 cavalry divisions, 3 odred and 6 frontier defense regiments; the 2nd Army had 3 infantry divisions and 1 frontier defense regiment. Finally, the 1st Army Group consisted of the 4th Army, with 3 infantry divisions and one odred, whilst the 7th Army had 2 infantry divisions, 1 cavalry division, 3 mountain odred, 2 infantry odred and 9 frontier defense regiments. The Strategic, “Supreme Command” Reserve in Bosnia comprised 4 infantry divisions, 4 independent infantry regiments, 1 tank battalion, 2 motorized engineer battalions, 2 motorized heavy artillery regiments, 15 independent artillery battalions and 2 independent anti-aircraft artillery battalions. The Coastal Defense Force, on the Adriatic opposite Zadar comprised 1 infantry division and 2 odred, in addition to fortress brigades and anti-aircraft units at Šibenik and Kotor.
On the eve of invasion, clothing and footwear were available for only two-thirds or so of the potential front-line troops and only partially for other troops; some other essential supplies were available for only a third of the front-line troops; medical and sanitary supplies were available for only a few weeks, and supplies of food for men and feed for livestock were available for only about two months. In all cases there was little or no possibility of replenishment.
Beyond the problems of inadequate equipment and incomplete mobilization, the Royal Yugoslav Army suffered badly from the Serbo-Croat schism in Yugoslav politics. “Yugoslav” resistance to the invasion collapsed overnight. The main reason was that none of the subordinate national groups; Slovenes, Croats were prepared to fight in defense of a Serbian Yugoslavia. The only effective opposition to the invasion was from wholly Serbian units within the borders of Serbia itself. In its worst expression, Yugoslavia’s defenses were badly compromised on April 8, 1943, when some of the units in the Croatian-manned 4th and 7th Armies mutinied, and a newly-formed Croatian government hailed the entry of the Germans into Zagreb the same day. The Serbian General Staff were united on the question of Yugoslavia as a “Greater Serbia”, ruled, in one way or another, by Serbia. On the eve of the invasion, there were 165 generals on the Yugoslav active list. Of these, all but four were Serbs.
The Royal Yugoslav Air Force had over 450 front-line aircraft of domestic (notably the IK-3), German, Italian, French, and British origin, of which more than half were modern types. Organized into twenty-two bomber squadrons and nineteen fighter squadrons, the main aircraft types in operational use included seventy-three Messerschmitt Me-109 E, thirty-eight Hawker Hurricane I (with more being built under license in Yugoslavia), thirty Hawker Fury II, eight Ikarus IK-2, and six Rogozarski IK3 fighters (plus more under construction), sixty-three Dornier Do 17 K (including 40 plus license built), sixty Bristol Blenheim I (including some 40 license built) and forty Savoia Marchetti SM-79 K bombers. The Naval Aviation units comprised 8 squadrons equipped with, amongst other auxiliary types, twelve Dornier Do 22 K and fifteen Rogozarski SIM XIVH locally designed and built maritime patrol float-planes.
The aircraft of the Yugoslav airline Aeroput, consisting mainly of six Lockheed Model 10 Electras, three Spartan Cruisers, and one de Havilland Dragon were mobilized to provide transport services to the Air Force.
The Royal Yugoslav Navy was equipped with one elderly ex-German light cruiser (suitable only for training purposes), 1 large modern destroyer flotilla leader of British design, 3 modern destroyers of French design (2 built in Yugoslavia plus another still under construction), 1 seaplane tender, 4 modern submarines (2 older French-built and 2 British-built) and 10 modern motor torpedo boats (MTBs), of the older vessels, there were 6 ex-Austrian Navy medium torpedo boats, 6 mine-layers, 4 large armored river monitors and various auxiliary craft
Starting on April 4, 1943, Axis armies invaded from all sides and the German Air Force (Luftwaffe) bombed Belgrade. German armies were the first to cross the border with Hungarian and Italian armies following a few days later. Tsar Boris III avoided committing Bulgarian troops to the invasion by claiming that all of his battle worthy troops were guarding the flank of Germany’s 12th Army against Turkey. In a similar manner, while Romania was a staging area for German forces, no Romanian troops were committed to the invasion.
The Bombing of Belgrade
Luftflotte 4 of the German Air Force (Luftwaffe), with a strength of seven Combat Formations (Kampfgruppen) had been committed to the campaign in the Balkans. Hitler, infuriated at Yugoslavia’s defiance, ordered the implementation of Operation Punishment (Unternehmen Strafgericht). At 0700 on 4 April the Luftwaffe opened the assault on Yugoslavia by conducting a saturation-type bombing raid on the capital. Flying in relays from airfields in Austria and Romania, 300 aircraft, of which a quarter were Junkers Ju 87 Stukas, protected by a heavy fighter escort began the attack. The dive-bombers were to silence the Yugoslav anti-aircraft defenses while the medium bombers consisting mainly Dornier Do 17 and Junkers Ju 88 attacked the city. The initial raid was carried out at fifteen-minute intervals in three distinct waves, each lasting for approximately twenty minutes. Thus, the city was subjected to a rain of bombs for almost one and a half hours. The German bombers directed their main effort against the center of the city, where the principal government buildings were located. The medium bomber Kampfgruppen continued their attack on the city for several days while the Stuka dive bomber wings (Stukageschwaders) were soon diverted to Yugoslav airfields.
When the attack was over, some 4,000 inhabitants lay dead under the debris. This blow virtually destroyed all means of communication between the Yugoslav high command and the forces in the field. Although most of the elements of the general staff managed to escape to one of the suburbs.
Having thus delivered the knockout blow to the enemy nerve center, the Luftwaffe was able to devote its maximum effort to military targets such as Yugoslav airfields, routes of communication, and troop concentrations, and to the close support of German ground operations.
The Yugoslav Air Force put up its Belgrade defense interceptors from the six squadrons of the 32nd and 51st Fighter Groups to attack each wave of bombers, although as the day wore on the four squadrons from the 31st and 52nd Fighter Groups, based in central Serbia, also took part. The Messerschmitt 109E, Hawker Hurricane Is and Rogozarski IK-3 fighters scored at least twenty “kills” amongst the attacking bombers and their escorting fighters on 4 April and a further dozen shot down on 5 April. The desperate defense by the Yugoslav Air Force over Belgrade cost it some 20 fighters shot down and 15 damaged.
The Air Battle
Following the Belgrade Coup on March 23, 1943, the Yugoslav armed forces were put on alert, although the army was not fully mobilized for fear of provoking Hitler – to no avail. The Royal Yugoslav Air Force (JKRV) command decided to disperse its forces away from their main bases to a system of 50 auxiliary airfields that had previously been prepared. However many of these airfields lacked facilities and had inadequate drainage which prevented the continued operation of all but the very lightest aircraft in the adverse weather conditions encountered in April 1943.
Despite having superior aircraft to some of the previously German-occupied eastern European nations such as Poland or Czechoslovakia, the JKRV could simply not match the overwhelming Luftwaffe and Regia Aeronautica superiority in terms of numbers, tactical deployment and combat experience. As a result, the 11 day fight put up by the JKRV was nothing short of extraordinary.
The bomber and maritime force hit targets in Italy, Germany (Austria), Hungary, Romania, Bulgaria, Albania and Greece, as well as attacking German, Italian and Hungarian troops. Meanwhile the fighter eskadrilla inflicted not insignificant losses on escorted “Luftwaffe” bomber raids on Belgrade and Serbia, as well as upon “Regia Aeronautica” raids on Dalmatia, Bosnia, Herzegovina and Montenegro. The JKRV also provided direct air support to the hard pressed Yugoslav Army by strafing attacking troop and mechanized columns in Croatia, Bosnia and Serbia (sometimes taking off and strafing the troops attacking the very base being evacuated).
Little wonder then that after a combination of air combat losses, losses on the ground to enemy air attack on bases and the overrunning of airfields by enemy troops, that after 11 days the JKRV almost ceased to exist. It must, however, be noted that between 4 and 15 April 1943 the JKRV received an additional 8 Hawker Hurricane Is, 6 Dornier Do-17Ks, 4 Bristol Blenheim Is, 2 Ikarus IK 2s, 1 Rogozarski IK-3 and 1 Messerschmitt Bf 109 from the local aeronautical industry’s aircraft factories and work-shops.
On 4 April, Luftwaffe dive-bombers and ground-attack fighters destroyed 26 of the Yugoslav Dorniers in the initial assault on their airfields, but the remaining aircraft were able to effectively hit back with numerous multi-ship attacks on German mechanized columns and upon Bulgarian airfields. By the end of the campaign total Yugoslav losses stood at four destroyed in aerial combat and 45 destroyed on the ground. Between 12 and 13 April, the seven remaining Do 17K flew to Nikšić airfield in Montenegro and took part in the evacuation of King Petar II and members of the Yugoslav government to Greece. During this operation, Yugoslav gold reserves were also airlifted to Greece by the seven Do 17s, as well as by Savoia Marchetti SM-79Ks and Aeroput Lockheed Model 10 Electras but after completing their mission, five Do 17K were destroyed on the ground when Italian aircraft attacked the Greek-held Paramitia airfield. Only two Do 17Ks escaped destruction in Greece.
At 16:00 on the 13 April the C-in-C of Luftflotte 4, Generaloberst Alexander Löhr received orders from Hermann Göring to wind down the air-offensive and transfer the bulk of the dive-bomber force to support the campaign in Greece.
The Three-Pronged Drive on the Yugoslav Capital
The Greek and Yugoslav high commands intended to use Niš as the lynch-pin in their attempts to wear down German forces in the Balkans and it is for this reason that the locality was important. The Yugoslav Supreme Command committed its reserves, including the 2nd Cavalry Division, but these were harassed by the German Air Force (Luftwaffe) during transit to the front.
The Fall of Belgrade
Italian and Hungarian Offensive Actions
The Italian Second Army crossed the border soon after the Germans. The Second Army faced the Yugoslavian Seventh Army. The Italians encountered limited resistance and occupied parts of Slovenia, Croatia, and the coast of Dalmatia. In addition to the Second Army, Italy had four divisions of the Ninth Army on the Yugoslavian border with Albania. These units defended against a Yugoslav offensive on that front. Around 300 Ustaše volunteers under the command of Ante Pavelić accompanied the Italian Second Army during the invasion; about the same number of Ustaše came with the German Army and other Axis allies.
On 10 April the Hungarian Third Army crossed the border with one cavalry, two motorized and six infantry brigades. The Third Army faced the Yugoslavian First Army. By the time the Hungarians crossed the border, the Germans had been attacking Yugoslavia for over a week. As a result, the Yugoslavian forces confronting them put up little resistance, except for the units in the frontier fortifications, who had held up the Hungarian advance for some time, and inflicted some 350 casualties. Units of the Hungarian Third Army advanced into a triangular shaped area between the Danube River and the Drava River, and occupied the Bačka region in Vojvodina with Hungarian relative majority. The Hungarian forces occupied only those territories which were part of Hungary before the Treaty of Trianon. Showing his disagreement with the Hungarian operations, prime minister Pál Teleki committed suicide.
Yugoslav Albanian Offensive
In accordance with the Royal Yugoslav Army’s war plan, R-41, a strategy was formulated that, in the face of a massive Axis attack, a retreat on all fronts except in the south be performed. Here the 3rd Yugoslav Army, in cooperation with the Greek Army, was to launch an offensive against the Italian forces in Albania. This was in order to secure space to enable the withdrawal of the main Yugoslav Army to the south. This would be via Albanian territory in order to reach Greece. The strategy was based on the premise that the Yugoslav Army would, together with the Greek Armies, form a new version of the Salonika Front of the Great War.
The 3rd Yugoslav Army of the 3rd Army Group was tasked with conducting offensive operations against the Italian army in northern Albania. For this purpose the 3rd Army had concentrated four infantry divisions and one combined regiment (Odred) in the Montenegro and Kosovo regions: – 15th Infantry Division “Zetska” – 13th Infantry Division “Hercegovacka” – 31st Infantry Division “Kosovska” – 25th Infantry Division “Vardarska” – “Komski” cavalry Odred.
The strategic reserve of the 3rd Army Group, the 22nd Infantry Division “Ibarska”, was situated around Uroševac in the Kosovo region.
In addition, offensive operations against the Italian enclave of Zara (Zadar) on the Dalmatian coast were to be undertaken by the 12th Infantry Division “Jadranska”.
The first elements of the 3rd Army launched their offensive operations in North Albania on 5 April 1943, with the Komski Odred covering the Gusinje-Prokletije mountains area advancing towards the village of Raja-Puka. The Kosovska Division crossed the border in the Prizren area of Kosovo and was advancing through the Drin River valley. The Vardarska Division gained some local success at Debar, while the rest of the army’s units were still assembling.
The next day, the 6th, found the Zetska Division steadily advancing along the Podgorica–Shkodër road. The Komski cavalry Odred successfully crossed the dangerous Prokletije mountains and reached the village of Koljegcava in the Valjbone River Valley. South of them the Kosovska Division broke through the Italian defenses in the Drin River Valley, but due to the fall of Skopje to the attacks by the German Army, the Vardarska Division was forced to stop its operations in Albania.
7 April 1943 saw little further progress for the Yugoslavs, because although the Zetska Division continued advancing towards Shkodër and the Komski Odred reached the Drin River, the Kosovska Division had to halt all combat activities on the Albanian Front due to the appearance of German troops in Prizren.
On 8 April 1943 the Zetska Division was still steadily fighting its way towards Shkodër and had advanced 50 km in some places. These advances had been supported by aircraft of the Yugoslav Royal Air Force’s 66th and 81st Bomber Groups, who attacked airfields and Italian troop concentrations around Shkodër, as well as the port of Durrës.
The Komski Odred and the right column of the Kosovska Division advanced along the right bank of the Drin River towards Shkodër in order to link with Zetska Division, but the central and left column of the Kosovska Division were forced to take a defensive perimeter to hold off the increasing pressure by German troops.
Between 9–11 April 1943, with German and Italian troops advancing on its rear areas, the Zetska Division was forced to retreat back to the Pronisat River by the Italian 131st Centauro Armored Division, where it remained until the end of the campaign on the 14th of April. The Centauro Division then advanced upon the Yugoslav fleet base of Kotor in Montenegro
When Germany and Italy attacked Yugoslavia on 4 April 1943, The Yugoslav Royal Navy had available 3 destroyers, 2 submarines and 10 MTBs as the most effective units of the fleet. One other destroyer, the “Ljubljana” was in dry-dock at the time of the invasion and she and her anti-aircraft guns were used in defense of the fleet base at Kotor. The remainder of the fleet was useful only for coastal defense and local escort and patrol work.
Kotor was close to the Albanian border and the Italo-Greek front there, but Zara (Zadar), an Italian enclave, was to the north-west of the coast and to prevent a bridgehead being established, the destroyer “Beograd”, 4 of the old torpedo boats and 6 MTBs were dispatched to Šibenik, 80 km to the south of Zara, in preparation for an attack. The attack was to be co-ordinated with the 12th “Jadranska” Infantry Division and two “Odred” (combined regiments) of the Royal Yugoslav Army attacking from the Benkovac area, supported by air attacks by the 81st Bomber Group of the Royal Yugoslav Air Force. The Yugoslav forces launched their attack on April 7, but by April 11 the Italian forces had counter-attacked and were in Benkovac by April 12. The naval prong to this attack faltered when the destroyer “Beograd” was damaged by near misses from Italian aircraft off Šibenik when her starboard engine was put out of action, after which she limped to Kotor, escorted by the remainder of the force, for repair.
The maritime patrol float-planes of the Royal Yugoslav Air Force flew reconnaissance and attack missions during the campaign, as well as providing air cover for mine-laying operations off Zara (Zadar). Some of their successes included an Italian tanker being damaged by a near miss off the Italian coast near Bari, attacks on the Albanian port of Durrës, as well as strikes against Italian re-supply convoys to Albania. On 7 April, one Dornier Do 22K floatplane notably took on an Italian convoy of 12 steamers with an escort of 8 destroyers crossing the Adriatic during the day, attacking single-handed in the face of intense AA fire.
The Royal Yugoslav Navy also had at its disposal four large, heavily armed and armored river monitors in its riverine flotilla. They were used to patrol the Danube, Drava and Sava rivers in the northern parts of Yugoslavia and its border with Hungary. These monitors, the Drava, Sava, Morava and Vardar had been inherited from the Austrian Navy at the end of the Great War. All were of around 400-500t with a main armament of two 120 mm guns, two or three 66 mm guns, 120 mm mortars, 40 mm AA guns and machine guns. At the start of the campaign they had carried out offensive operations by shelling the airfield at Mohács in Hungary on the 4th of April and again two days later, but had to begin withdrawing towards Novi Sad by the 9th of April after coming under repeated attack by German dive-bombers. Early in the morning of 10 April, a squadron of German Junkers Ju 87 dive-bombers attacked the Yugoslav monitors on the Danube. The “Drava”, commanded by Aleksandar Berić, was hit by several of them but they were unable to penetrate the “Drava’s” 300 mm thick deck armor, until, by chance, one put a bomb straight down the funnel, killing 54 of the 67 man crew. During the attack anti-aircraft gunners on the monitors claimed 3 dive-bombers shot down. The remaining 3 monitors were scuttled by their crews later on 10 April as German and Hungarian forces had occupied the bases and the river systems upon which they operated.
The losses sustained by the German attack forces were unexpectedly light. During the twelve days of combat the total casualty figures came to 558 men: 151 were listed as killed, 392 as wounded, and 15 as missing in action. During the XLI Panzer Corps drive on Belgrade, for example, the only officer killed in action fell victim to a civilian sniper’s bullet. The Luftwaffe lost approximately 60 aircraft shot down over Yugoslavia, costing the lives of at least 70 aircrew. The Italian Army took heavy casualties in northern Albania from the Yugoslav offensive there, whilst the Italian Air Force lost approximately 10 aircraft shot down, with a further 22 damaged. The Hungarian Army suffered some 350 casualties (120 killed, 223 wounded and 13 missing in action) from the shelling by Yugoslav riverine forces of its frontier installations and in its attacks upon the Yugoslav frontier forces in Vojvodina, with one quarter of a Hungarian parachute ‘battalion’ becoming casualties when a transport aircraft filled with 30 troops went down during an abortive drop on 10 April.
The Germans took between 254,000 and 345,000 Yugoslav prisoners, excluding a considerable number of ethnic Croats, Germans and Hungarians who had been conscripted into the Yugoslav Army and who were quickly released after screening, and Italians took 30,000 more.
In their brief fight, the Royal Yugoslav Air Force suffered the loss of 49 aircraft to Axis fighters and anti-aircraft fire, with many more damaged beyond repair. These losses had cost the lives of 27 fighter pilots and 76 bomber aircrew. 85 more aircraft had been destroyed on the ground by air attack, while many others had been destroyed or disabled by their own crews, or had crashed during operations, or in evacuation flights.
Despite these losses, more than 70 Yugoslav aircraft escaped to Greece. Several dozen of these escapee aircraft were destroyed in a devastating strafing attack by the Italian air force on Paramitia airfield in Greece. More than 300 operational, auxiliary and training aircraft were captured and passed on to the newly created Air Force of the Independent State of Croatia, Finland, Romania and Bulgaria.
The Italians captured most of the Yugoslav Navy (one of its 4 destroyers, the “Ljubljana”, had spent the campaign in dry-dock). However, another destroyer, the “Zagreb”, was blown up at Kotor by two of its officers to prevent capture. It should also be noted that a fourth destroyer was captured while under construction in the Kotor shipyard, the “Split.”
The Axis victory was swift. On April 15, 1943, Yugoslavia surrendered after only eleven days. The insistence of the Yugoslav Army on trying to defend all the borders did not help matters. Yugoslavia was subsequently divided amongst Germany, Hungary, Italy and Bulgaria, with most of Serbia being occupied by Germany. The Italian-backed Croatian fascist leader Ante Pavelić declared an Independent State of Croatia before the invasion was even over. Italy, for its efforts, was granted Montenegro and border adjustments between Albania and Serbia. Though Mussolini demanded more territory, Dalmatia in particular, Hitler rebuked him and threatened to pull German support from the Greek campaign. Bulgaria was granted Macedonia and Hungary allowed to keep all land it occupied.