Belgrade offensive
The Belgrade offensive or the Belgrade strategic offensive operation was a military operation during World War II in Yugoslavia in which Belgrade was liberated from the German Wehrmacht through the joint efforts of the Soviet Red Army, Yugoslav Partisans, and the Bulgarian Army. Soviet forces and local militias launched separate but loosely cooperative operations that undermined German control of Belgrade and ultimately forced a retreat. Martial planning was coordinated evenly among command leaders, and the operation was largely enabled through tactical cooperation between Josip Broz Tito and Joseph Stalin that began in September 1944. These martial provisions allowed Bulgarian forces to engage in operations throughout Yugoslav territory, which furthered tactical success while increasing diplomatic friction.
The primary objectives of the Belgrade offensive centered on lifting the German occupation of Serbia, seizing Belgrade as a strategic holdout in the Balkans, and severing German communication lines between Greece and Hungary. The spearhead of the offensive was executed by the Soviet 3rd Ukrainian Front in coordination with the Yugoslav 1st Army Corps. Simultaneous operations in the south involved the Bulgarian 2nd Army and Yugoslav XIII Army Corps, and the incursion of the 2nd Ukrainian Front northwards from the Yugoslav-Bulgarian border placed additional pressure on German command. There were additional skirmishes between Bulgarian forces and German anti-partisan regiments in Macedonia that represented the campaign's southernmost combat operations.
Background
Developments in Yugoslavia
In August 1943, the German Wehrmacht had two army formations deployed in the Balkans: Army Group E in Greece and the 2nd Panzer Army in Yugoslavia and Albania. Army Group F headquarters in Belgrade acted as a joint high command for these formations, as well as for Bulgarian and Quisling formations.After the collapse of the uprising in December 1941, anti-Axis activity in Serbia decreased significantly, and the focus of resistance moved to other, less populated areas. Consequently, although Serbia had great significance to the Germans, very few troops actually remained there; according to Schmider only about 10,000 in June 1944. In the following years, Tito repeatedly tried to reinforce the partisan forces in Serbia with experienced units from Bosnia and Montenegro. From the spring of 1944, the Allied command had assisted in these efforts. The Germans actively opposed these efforts by concentrating forces in the border regions of Bosnia and Montenegro, in order to disturb Partisan concentrations, to inflict casualties on Partisan units, and to push them back with a series of large-scale assaults.
In July 1944, German defenses began to fail. After the failure of Operation Draufgänger – a 1944 anti-partisan operation in Montenegro, Yugoslavia, and Northern Albania – three divisions of the Narodnooslobodilačka vojska Jugoslavije – managed to cross the Ibar River to the east and threaten the main railroad lines. After the failure of Operation Rübezahl in Montenegro in August 1944, two additional NOVJ divisions broke through the German blockade, successfully entrenching themselves in western Serbia. Army Group F command responded by deploying additional forces: the 1st Mountain Division arrived in Serbia in early August, followed by the 4th SS Panzergrenadier Division from the Thessaloniki area.
Developments in Romania in late August 1944 confronted Army Group F command with the necessity of an immediate large-scale concentration of troops and weapons in Serbia in order to cope with a threat from the east. The Allied command, and the NOVJ supreme command, predicted this scenario and developed a plan for the occasion. On 1 September 1944, a general attack from the ground and from the air on the German transport lines and installations began. These attacks largely hindered German troop movements, with units disassembled and tied to the ground.
In the meantime, the 1st Proletarian Corps, the main partisan formation in Serbia, continued with reinforcing and developing its forces and with seizing positions for the assault on Belgrade. On 18 September Valjevo was taken, and on 20 September Aranđelovac. Partisans achieved control of a large area south and southwest of Belgrade, thus forming the basis for the future advance towards Belgrade.
In response to the defeat of German forces in the Second Jassy–Kishinev offensive in late August 1944, which forced Bulgaria and Romania to switch sides, and to the advance of Red Army troops into the Balkans, Berlin ordered Army Group E to withdraw into Hungary. But the combined actions of Yugoslav partisans and Allied air forces impeded German movements with Ratweek. With the Red Army on Serbia's borders, the Wehrmacht put together another provisional army formation from available elements of Army Group E and the 2nd Panzer Army for the defense of Serbia, called "Army Group Serbia".
Regional developments
As a result of the Bulgarian coup d'état of 1944, the pro-Axis regime in Bulgaria was overthrown and replaced with a government of the Fatherland Front led by Kimon Georgiev. Once the new government came to power, Bulgaria declared war on Germany. Under the new pro-Soviet government, four Bulgarian armies, 455,000 strong were mobilized and reorganized. In early October 1944, three Bulgarian armies, consisting of around 340,000 men, were located on the Yugoslav – Bulgarian border.By the end of September, the Red Army 3rd Ukrainian Front troops under the command of Marshal Fyodor Tolbukhin were concentrated at the Bulgarian-Yugoslav border. The Soviet 57th Army was stationed in the Vidin area, while the Bulgarian 2nd Army was stationed to the south on the Niš rail line at the junction of the Bulgarian, Yugoslav, and Greek borders. This allowed the arrival of the Partisans 1st Army from Yugoslav territory, in order to provide support to their 13th and 14th Corps collaborating in the liberation of Niš and supporting the 57th Army's advance to Belgrade, respectively. The Red Army 2nd Ukrainian Front's 46th Army was deployed in the area of the Teregova river, poised to cut the rail link between Belgrade and Hungary to the north of Vršac.
Pre-operations were coordinated between the Soviets and the commander-in-chief of the Yugoslav Partisans, Marshal Josip Broz Tito. Tito arrived in Soviet-controlled Romania on 21 September, and from there flew to Moscow where he met with Soviet premier Joseph Stalin. The meeting was a success, in particular because the two allies reached an agreement concerning the participation of Bulgarian troops in the operation that would be conducted on Yugoslav territory.
The offensive
Before the start of ground operations, the Soviet 17th Air Army was ordered to impede the withdrawal of German troops from Greece and southern regions of Yugoslavia. To do so, it carried out air attacks on the railroad bridges and other important facilities in the areas of Niš, Skopje, and Kruševo lasting from 15 to 21 September.Plan of the offensive
It was necessary for the Yugoslavs to break through German defensive positions on the Yugoslav-Bulgarian border to gain control of roads and mountain passages through eastern Serbia, to penetrate into the valley of the Great Morava river, and to secure the bridgehead on the western bank. This task was to be executed mainly by the 57th Army, and the Yugoslav XIV Army Corps was ordered to co-operate and support the Red Army attack behind the front line.After the successful completion of the first stage, the plan was to deploy the 4th Guards Mechanized Corps to the bridgehead on the west bank. This Corps with its tanks, heavy weapons, and impressive firepower was compatible with the Yugoslav 1st Army Corps, which had significant, concentrated manpower, but was armed mainly with light infantry weapons. Once joined, these two formations were ordered to execute the main attack on Belgrade from the south. The advantages of this plan were the possibility of the rapid deployment of forces in the critical final stage of the offensive, and the possibility of cutting off German troops in eastern Serbia from their main forces.
First stage
Local situation
In January 1944, partisan operational units left the northern part of east Serbia under pressure from occupiers and auxiliary forces. Bulgarian garrisons, some German police forces, and Serbian Quisling troops, all under German command, and Chetniks, mostly commanded by agreements with the Germans, remained in the area. Partisan forces made up of the 23rd and 25th Divisions returned to the central parts of east Serbia in July and August 1944, forming a free territory with a makeshift runway in Soko Banja, thus securing both air supply of arms and ammunition, and allowing evacuation of the wounded. After the coup in Romania, the importance of the northern part of east Serbia had grown for both sides. In a race against each other the Partisans were better positioned and faster. 23rd Division, in a fierce battle with Order Police battalions and auxiliary forces, took Zaječar on 7 September, and on 12 September entered Negotin, while the 25th Division unsuccessfully attacked Donji Milanovac at the same time. Volunteers were joining the units in large numbers increasing their size. A new, 45th Serbian Division was formed on 3 September, and on 6 September, 14 Corps headquarters was established as a high command for the area of operations.The Germans intervened with the 1st Mountain Division, reaching Zaječar on 9 September. Over the next week Partisans launched defensive attacks trying to deny the Germans access to the Danube at Negotin. On 16 September, when Red Army forces did not cross over from Romania as expected, the 14th Corps decided to abandon its defense of the Danube coastline, and to focus on attacking German columns maneuvering elsewhere.
On 12 September, near Negotin, a NOVJ delegation led by Colonel Ljubodrag Đurić crossed the Danube to the Romanian side, and establish contact with the Red Army 74th Rifle Division. The delegation was accompanied to Romanian territory by the 1st Battalion of the 9th Serbian Brigade; the 1st Battalion would fight with the 109th Regiment of 74th Rifle Division until 7 October.
In August 1944, Weichs ordered the concentration of his mobile forces in Serbia to combat the Partisans. This included: the 4th SS Police Division, the 1st Mountain Division, the 92nd Motorized Regiment, the 4th Brandenburg Regiment, the 191st Assault Brigade, and the 486th Armored Reconnaissance Troop. As a counter-measure to the events in Romania and Bulgaria, he ordered the 11th Luftwaffe Field Division, the 22nd Infantry, the 117th, the 104th Jäger Division, and the 18th SS Mountain Police Regiment to advance to Macedonia.
The 1st Mountain Division was withdrawn from operations against partisans in Montenegro, and was transported to the Niš area. On 6 September, it was placed under the command of General Hans Felber, tasked with establishing control on the Bulgarian border. By mid-September, the division won control of Zaječar and reached the Danube, at the area where the main attack was expected. The 7th SS Division under the command of the 2nd Panzer Army, attacked partisan units moving to Serbia from eastern Bosnia and Sandžak. This Division was subordinated to General Felber on 21 September, with the intention of launching an offensive against the partisans in western Serbia. However, due to the deteriorating situation on the eastern border, this offensive was canceled. Beginning at the end of September, the division was transferred to southeast Serbia, to guard the southern part of the Serbian front-line between Zaječar and Vranje. This enabled the 1st Mountain Division to concentrate on the north, in the area between Zaječar and Iron Gates. The 1st Mountain Division was strengthened by the 92 Motorized Regiment, the 2nd Brandenburg, and the 18th SS Mountain Police Regiment. Both divisions added men from sections of German units withdrawn from Romania, and Bulgaria, as well as from local formations. On 22 September, the 1st Mountain Division mounted an attack on the left bank of the Danube in order to gain control of the Iron Gates, but the plan failed when the 75th Corps of the Red Army, advancing in the opposite direction, launched an attack on the division.