Soviet Union in the Korean War Though not officially belligerent in the Korean War ( 1950 – 1953 ) , the communist Soviet Union played a significant , covert role in the conflict through its provision of material and medical services and also Soviet pilots and aircraft ( most notably MiG 15 jet fighters ) to aid the North Korean - Chinese forces engaged in combat with United Nations Forces . Background . Soviet Occupation of Northern Korea ( 1945 - 1948 ) . The Soviet 25th Army took part in the Soviet advance into northern Korea immediately after World War II had ended , and was headquartered at Pyongyang for a period . Like the American forces in the south , Soviet troops remained in Korea after the end of the war to rebuild the country . Soviet soldiers were instrumental in the creation and early development of the North Korean People ' s Army and Korean People ' s Air Force , as well as for stabilizing the early years of the Northern regime . The Shineuiju Air Force Academy was founded under Soviet leadership on 25 October 1945 in order to train new pilots . Cold War . Because at the time the war broke out in 1950 , the Communist Soviet Union , China and their allies were already locked into a " Cold War " with capitalist countries , both sides felt that the Korean conflict carried the potential to further destabilize the precarious relations between both sides , while also offering possible advantages . As American and UN soldiers were deployed in the conflict on the South Korean side , a Soviet declaration of war on the South would have led to a war with other UN countries . Instead , the Soviet Union was forced to hide its participation in the conflict so as not to risk escalating the " Cold War " into a " Hot War " with NATO and the United States elsewhere , which could have led to a nuclear war . By officially denying its participation , the Korean War was not allowed to escalate . Participation on the North Korean side was also contrary to the UN Security Council Resolution 84 which the Soviet Union was technically bound by . Soviet Aid to North Korean Forces . Medical Aid . Along with several " Eastern Block " countries ( notably Czechoslovakia ) , the Soviet Union sent over 20 doctors to Korea to aid Communist forces there , similar to Italian , Norwegian , Danish and Swedish medical detachments in Southern Korea who did not have military force engaged , but merely offered humanitarian support instead . War Material Aid . Soviet military aid was instrumental to equipping both North Korean and Chinese armies in Korea . The Soviet PPSh - 41 ( nicknamed by US forces the " " Burp Gun " " after the sound it made ) was widely supplied to both armies , as was the T - 34 / 85 tank which was of great importance during the first offensive when no US armour or anti - tank rockets could penetrate its armour . Soviet material aid was also fundamental for the air force . By April 1950 , the Soviet Union had provided 63 of the air force ' s 178 aircraft . Soviet Air Intervention . One of the most important areas in which Soviet intervention was key in the Korean War was in the air - war . Soviet innovation in aircraft design , as well as the experience of many of its pilots following the Second World War meant that the ' new ' states of China and North Korea were dependant on Soviet help in this area . Both the Chinese and North Korean air forces were structured and equipped along Soviet lines because of the help that the Soviet Union had given them in their first years . In October 1950 , the Chinese air force comprised only two fighter divisions , one bomber regiment , and one attack aircraft regiment ( a total of two hundred combat planes ) and was very much in its infancy . The Chinese committed several Air Regiments to Korea , and these were equipped with the Soviet - supplied MiG 15 fighters , however lack of training meant that the Chinese high command was anxious for Soviet pilots , some of whom were already in China tasked with training the pilots for the Chinese air force . Frustrated by the quality and shortage of Chinese pilots , in April 1951 , Stalin took the decision to involve Soviet airforce pilots in the war , flying under the markings of the Chinese People ' s Liberation Army Air Force ( PLAAF ) or North Korean Peoples ' Army Air Force ( KPAAF ) . In addition to the widely known MiG - 15 force of 64th Fighter Corps , there were also significant anti - aircraft gun , searchlight and technical units despatched to Korea as part of the same unit . Soviet Pilots . Soviet pilots were active in Korea from April 1951 . In order to hide this direct Soviet intervention , precautions were taken to disguise their involvement , open knowledge of which would have been a major diplomatic embarrassment for the USSR . Soviet pilots wore Chinese uniforms when flying , whilst rules were prescribed to stop Sovet pilots flying near the coast or front lines ( where they might be captured if shot down ) and from speaking Russian on the aircraft radio . All aircraft flown carried Chinese or North Korean markings . When not flying , for reasons of ethnicity , on the ground Soviet pilots ' played ' the roles of Soviet commercial travellers rather than Chinese or North Korean soldiers . Soviet pilots flying MiG 15 jets participated in battles around the Yalu River Valley on the Chinese - Korean border in the area known as " Mig Alley " and in operations against UN " trainbusting " attacks in Northern Korea , with considerable success . The lack of a shared language between Soviet , Chinese and North Korean pilots frequently led to incidences of friendly fire as other MiG fighters were mistaken for American F - 86 Sabre jets and shot down . MiG 15s . The MiG 15 was a jet aircraft , supplied in large numbers to Chinese and North Korean forces during the war by the Soviet Union . Owing to their modern design ( they were at least a match for the best American jet fighter of the time , the F - 86 Sabre ) , they played a pivotal role in the air war . At the outbreak of the war , the North Koreans flying Soviet aircraft like the IL - 10 ground attack aircraft and Yak - 9P fighters were easily outclassed by modern American jet aircraft such as Lockheed F - 80 Shooting Star and Republic F - 84 Thunderjet ) fighters , which meant that UN forces quickly achieved air superiority . By contrast , when the MiG 15 appeared in Korea , it immediately challenged this air superiority , since it could outclass all fixed - wing American jets in Korea at the time ( not to mention the aged propeller - driven P - 51 Mustang ) . It is believed that Soviet pilots ( who all flew MiG 15s ) shot down 142 - 1 , 106 UN aircraft ( depending on whose estimate is used ) during the duration of the conflict , a higher kill total than that of comparable UN units . Despite this superior performance , the MiGs main goal was to counter the USAF B - 29 Superfortress bombers rather than dogfight with other fighters . Recognising the importance of the MiG , the UN command devised Operation Moolah to encourage a MiG pilot to defect to South Korea with a functional MiG for testing . $ 100 , 000 ( USD ) and political asylum were offered as a reward , and North Korean pilot Lieutenant No Kum - Sok eventually defected in September 1953 ( claiming to be unaware of the reward ) , finally providing the US with an example for testing . Contemporary awareness of Soviet participation . Though the Soviet Union never acknowledged its participation in the conflict , it is clear that many suspected it . Soviet pilots , though forbidden from communicating in any language other than basic Korean across their radios , often resorted to Russian when stressed or when swearing . This was picked up by American pilots . These reports were always denied by the Soviet Union and it was only recently with the publication of books by Chinese and Russian authors , such as Zhang Xiaoming , Leonid Krylov , Yuriy Tepsurkaev and Igor Seydov that it became clear . Legacy for Sino - Soviet Relations . Contrary to expectations , the Soviet intervention in Korea did not inspire the Chinese leadership with confidence . Mao , in particular , felt betrayed that the Soviet leadership had refused to send infantry and armoured units , in addition to its MiG squadrons , and join the conflict openly beside China . There is evidence that the Chinese felt restricted by the Russians , who forced them to defer to the Soviet Union for technological and strategic support , but offered only minor support in exchange . Furthermore , the Chinese leadership felt humiliated by the Soviet decision to make the Chinese pay them for all the material support that they had received , which " made the Soviets seem more like arms merchants than genuine Communist internationalists . " In effect , Zhang Xiaoming argues that the Chinese came to feel that the Soviet Union was both an unreliable and demanding ally and took greater steps to ensure autarky from the USSR in the years following the War . In 1960 , China broke from the Soviet Union in an event known today as the Sino - Soviet Split , creating a rift amongst all communist powers which were expected to pick one side of the divide . This split , certainly influenced by the Korean War shaped relations between the two countries until 1989 .