After Operation Barbarossa had commenced on 22nd June 1941, Hungary initially dithered on whether or not to support the Axis invasion. The Hungarian government based its initial refusal to participate on Article 3 of the Axis Pact, which Hungary had joined on 29th September 1940. The Article provided that Hungary was not obliged to support Germany as the latter was the obvious aggressor and was not itself being attacked. There followed intense diplomatic pressure from Germany until 26th June 1941. On this date bombers of uncertain nationality bombed the Hungarian cities of Kassa and Munkacs, inflicting 320 casualties (37 killed) and substantial material damage. The remains of the bombs were examined and apparently they bore the markings of a Leningrad factory.
However, to this day the exact source of this air raid is unknown. Some claim the aircraft were Soviet, but why the Soviets would conduct a punitive air raid to bring another country into the war against her makes no sense. In addition the Soviets always denied that they sanctioned this raid. Some claim the raid was conducted by disgruntled Czech or Slovak pilots who had fled the German and Hungarian occupation and enlisted in one of the Allied air forces. On balance it seems the most likely source of the air raid was the Luftwaffe: they had the strategic motivation, possessed the highly experienced aircrew and specialist (or even captured) aircraft required, and had access to captured Soviet ordnance. If this was what happened then the air raids on Kassa and Munkacs amounted to one of the most successful clandestine operations of WWII: a small air raid that effectively brought another country into the war. It has to be said however that this was only the last straw, and that Hungary was already very much in the Axis fold.
On 27th June 1941 the Hungarian government declared war on the Soviet Union, although they had been mobilising their Mobile Corps and Air Defence Command since 22nd June. Always wary of their neighbours (particularly Rumania), the Hungarians kept the majority of their armed forces in Hungary during 1941. However their best units were sent East in support of Operation Barbarossa by early July 1941, initially grouped under the Hungarian Carpathian Army Group.
The Royal Hungarian Army and Royal Hungarian Air Force (Magyar Kiralyi Honved Legiero, MKH) Forces Available to Support Operation Barbarossa from 28th June to early July 1941
Carpathian Army Group
- Carpathian Army Group with 5 brigades and 93 010 personnel
- 1 mobile corps HQs, 1 artillery corps HQ, 2 motorised brigades, 1 cavalry brigade, 1 mountain brigade, and 1 border guard brigade.
- 141 light tanks and tankettes, 41 armoured cars, 117 combat aircraft (deployed with 1. Air Field Brigade only) *, 264 (37-149mm) artillery pieces (including 112 37mm AT guns),
- 78 (37-88mm) AA guns, 274 (50-80mm) mortars, and 5 716 motor vehicles (excluding 142 artillery prime movers, armoured cars and motorcycles).
- Commander: General Ferenc Szombathelyi.
* An additional 163 combat and transport aircraft were also deployed but not in support of the Carpathian Army Group, and an additional 204 combat and transport aircraft were not deployed with any front line aviation units. (Total 484 combat and transport aircraft in service, excluding light training aircraft).