Belgrade is Captured by German Forces
Since three separate attack forces were converging on Belgrade simultaneously, the Army High Command was not immediately able to determine which force was the first to reach the enemy capital.
Toward early evening of 12 April, SS-Obersturmfuhrer Klingenberg of the 2nd SS Division Das Reich, finding all Danube bridges destroyed, took an SS patrol across the river in captured pneumatic rafts. The patrol entered the city unmolested, and at 1700 hoisted a Swastika flag atop the German legation. About two hours later the mayor of Belgrade officially handed over the city to Klingenberg who was accompanied by a representative of the German Foreign Ministry, previously interned by the Yugoslavs.
At Second Army headquarters, no word from the 8th Panzer Division elements, which were last reported approaching the western outskirts of Belgrade, had been received for twenty-four hours. Finally, at 1152 on 13 April the following radio message came through from the operations officer of the division:
During the night the 8th Panzer Division drove into Belgrade, occupied the center of the city, and hoisted the Swastika flag.
However, since better communications had existed between Second Army and First Panzer Group, the following flash was received shortly before the 8th Panzer Division message came in:
Panzer Group von Kleist has taken Belgrade from the south. Patrols of Motorized Infantry Regiment Gross Deutschland have entered the city from the north. With General von Kleist at the head, the 11th Panzer Division has been rolling into the capital since 0632.
Thus the race for Belgrade ended in a close finish with all three forces reaching their objective almost simultaneously. With the fall of the city, the First Panzer Group was transferred from the Twelfth to the Second Army, while the XLVI Panzer Corps was placed under the direct command of the panzer group for the next phase of the operation - the pursuit and final destruction of the remnants of the Yugoslav Army.
The bombing of Belgrade on April 6 was the last stand the Kingdom took against the Axis powers. Although information is mostly sketchy, many sources say that Axis countries (in this case, Germany, Italy, and probably Hungary) deployed up to 2,000 combat aircraft during the bombing of Belgrade. The Royal Yugoslav Air Force's defenses were mostly obsolete. Many of its fighter planes were obsolete, some even with World War I-era technology. Out of 487 operational combat aircraft in the inventory of the Yugoslav Air Force in 1941, less than 150 of them were fit enough to pose a threat to modern Nazi fighters. During April 6th and 7th of 1941, the Yugoslav Air Force only downed about 90 to 100 enemy aircraft.
WWII at BBC