The bombing of Kassa took place on 26 June 1941, when still unidentified aircraft conducted an airstrike on the city of Kassa, then part of Hungary, today Košice in Slovakia. This attack became the pretext for the government of Hungary to declare war on the Soviet Union the next day, 27 June. On 26 June 1941, four days after Germany attacked the Soviet Union in violation of the Molotov–Ribbentrop non-aggression treaty as a part of Operation Barbarossa, three unidentified planes bombed the city, killing and wounding over a dozen people and causing minor material damage. Numerous buildings were hit, including the local post and telegraph office. Hours after the attack, the Hungarian cabinet "passed a resolution calling for the declaration of the existence of a state of war between Hungary and the USSR." The local military investigators at the time believed that the attackers were Soviet, but the true identity of the attacking nation has never been established. The official explanation preferred by Soviet historians was the idea of a feigned attack by Germany to provoke Hungary into attacking the Soviet Union, employing Soviet planes captured on conquered airfields. Another possibility is that the Soviet bombers mistook Kassa for a nearby city in the First Slovak Republic, which was already at war with the Soviet Union. Captain Ádám Krúdy, the commander of the Kassa military airfield, identified the attackers as German Heinkel He 111 bombers in his official report but was ordered to keep silent about it. Another problem with the German conspiracy theory was the fact that German planes did not have bomb-racks capable of holding Soviet bombs. According to Dreisziger, "it seems that the bombs dropped on Kassa were 100 kg bombs while the standard stock of the Luftwaffe were the 50 and 250 kg bombs." During the Nuremberg trials, the USSR brought forth a statement allegedly taken from Hungarian Major General István Újszászy. According to the testimony, "the Kassa 'plot' was hatched by German and Hungarian officers and carried out by 'German planes with Russian markings'." This theory was introduced because he found that, following the Kassa bombings, certain officers behaved suspiciously, not due to concrete evidence. The reliability of his testimony less valued due to the nature of his interrogation, which may have been under duress. In his memoirs, Admiral Miklós Horthy, Hungary's head of state in the interwar period, stated that Hungary's entry into World