[11] 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.

[12][13] These martial provisions allowed Bulgarian forces to engage in operations throughout Yugoslav territory, which furthered tactical success while increasing diplomatic friction.

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.

[citation needed] 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.

[23] 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.

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.

Before the start of ground operations, the Soviet 17th Air Army (3rd Ukrainian Front) was ordered to impede the withdrawal of German troops from Greece and southern regions of Yugoslavia.

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.

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.

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.

This started a race between the Soviets and the Germans to the "Blue Line", an intended front-line running from the southern slopes of the Carpathians over the Iron Gates down the Yugoslav-Bulgarian border.

[2] Vast terrain with poor and damaged roads, uncertainty over local forces, and logistical difficulties dispersed the German groups and slowed down their advancement.

Because of the lack of troops at the front-line, on 29 September, Army Group F Command ordered a defensive assault by the 1st Mountain Division and the 92nd Motorized Brigade in an attempt to buy time.

Having firm control of the crossroads in their area, Soviet command decided to postpone a decisive attack on the German battle groups and to exploit the open roads with mobile forces for deeper penetration.

In twenty-four hours the brigade performed a 120 km long march-maneuver, reaching the Great Morava valley on 8 October, leaving German frontline forces far behind.

[30] On 7 October 64th Rifle Corps units, together with elements of 45th Division NOVJ, finally managed to break the steadfast resistance of battle group Groth and took Zaječar.

Previous deployment of forces to the front-line in Serbia had already cost 2nd Panzer Army the loss of a number of important towns, some permanently: (Drvar, Gacko, Prijedor, Jajce, Donji Vakuf, Bugojno, Gornji Vakuf, Tuzla, Hvar, Brač, Pelješac, Berane, Nikšić, Bileća, Trebinje, Benkovac, Livno), and some temporarily: (Užice, Tešanj, Teslić, Slavonska Požega, Zvornik, Daruvar, Pakrac, Kolašin, Bijelo Polje, Banja Luka, Pljevlja, Virovitica, Višegrad, and Travnik).

Operations began on the far southern flank of the front with an offensive by the 2nd Bulgarian Army into the Leskovac-Niš area, which almost immediately engaged the infamous 7th SS Mountain Division "Prinz Eugen".

Supported by the 5th Air Army, its 10th Guards Rifle Corps was able to rapidly perform assault crossings of the rivers Tamiš and Tisa north of Pančevo to threaten the Belgrade-Novi Sad railroad.

[35] With this success, German forces were split into two separate groups: the Belgrade garrison to the west, and the battle-group retreating from eastern Serbia, which was then in the Smederevo area.

The 36th Tank Brigade continued northwards without delay, and 9 kilometers north of Topola encountered a German assault gun battalion marching in the opposite direction.

The Yugoslavs advanced along the roads in the direction of Belgrade south of the Sava River, while the Red Army engaged in fighting on the northern bank outskirts.

[citation needed] The assault on the city was delayed due to the diversion of forces for the elimination of thousands of German troops surrounded between Belgrade and Smederevo to the south-east.

The Soviet 10th Guards Rifle Corps of the 46th Army (2nd Ukrainian Front), together with units of the Yugoslav Partisans moving via the Danube, provided more offensive strength from the north-east against the Wehrmacht's position in Belgrade.

Upon completion of the Belgrade operation by the 57th Army with the Yugoslav 51st division in November, the bridgehead in Baranja, on the left bank of Danube was taken, causing an acute crisis for the German defense.

Having lost Belgrade and the Great Morava Valley, German Army Group E was forced to fight for a passage through the mountains of Sandžak and Bosnia, and its first echelons did not reach Drava until mid-February 1945.

[39] Since then, the country there has only been two military parades and high level celebrations in honor of the occasion in Yugoslavia and the Republic of Serbia, with the first one, the March of the Victor, being held on Nikola Tesla Boulevard with Russian President Vladimir Putin as the guest of honour.

[40] Every jubilee anniversary is met with a significant Russian presence, often coming in the form of a state visit by the President of Russia or another high-ranking official to Belgrade.

Beginning with Dmitry Medvedev in 2009 and continued with Vladimir Putin as aforementioned, the laying of wreaths of the President of Serbia and the leader of Russia takes place at the Liberators of Belgrade Memorial, which contains the remains of over 3,500 Yugoslav Partisans and Red Army soldiers who died during the offensive.