Over the course of its history, the Soviet Union intervened in foreign countries on numerous occasions.
Invasions of Afghanistan (1929-1930)
Two Soviet invasions of Afghanistan took place between 1929 and 1930.
The first intervention was a special operation aimed at supporting the ousted king of Afghanistan, Amanullah Khan, in a civil war against the Saqqawists and Basmachi. The Soviets occupied the Balkh Province however they withdrew after the King fled the country. Thus, the Saqqawists took control in January 1929.
The second intervention took place after the Afghan Saqqawist government allowed Basmachi insurgents (an anti-Russian Islamic movement) to operate from northern Afghanistan against the Soviets. Despite the overthrow of Saqqadist government in October 1929 and restoration of the monarchy, Basmachi bases remained in northern Afghanistan with threats of declaring independence from Afghanistan. As such the new Afghan government agreed to a Soviet intervention by June 1930. The result was the Basmachi bases largely being destroyed.
Invasion of China (1934)
In 1934, Ma Zhongying's troops, supported by the Kuomintang government of the Republic of China were on the verge of defeating the Soviet client Sheng Shicai during the Battle of Ürümqi (1933–34) in the Kumul Rebellion.
Ma Zhongying, a Hui (Chinese Muslim), had earlier attended the Whampoa Military Academy in Nanjing in 1929, when it was run by Chiang Kai-shek, who was also the head of the Kuomintang and leader of China.
Ma Zhongying then was sent back to Gansu after graduating from the academy and fought in the Kumul Rebellion where, with the tacit support of the Kuomintang government of China, he tried to overthrow the pro-Soviet provincial government first led by Governor Jin Shuren then Sheng Shicai. Ma invaded Xinjiang in support of Kumul Khanate loyalists and received official approval and designation from the Kuomintang as the 36th Division.
In late 1933, the Han Chinese provincial commander General Zhang Peiyuan and his army defected from the provincial government side to Ma Zhongying's side and joined him in waging war against Jin Shuren's provincial government.
In 1934, two brigades of about 7,000 Soviet GPU troops, backed by tanks, airplanes and artillery with mustard gas, crossed the border to assist Sheng Shicai in gaining control of Xinjiang. The brigades were named "Altayiiskii" and "Tarbakhataiskii". Sheng's Manchurian army was being severely beaten by an alliance of the Han Chinese army led by general Zhang Peiyuan, and the 36th Division led by Ma Zhongying. Ma fought under the banner of the Kuomintang Republic of China government. The joint Soviet-White Russian force was called "The Altai Volunteers". Soviet soldiers disguised themselves in uniforms lacking markings, and were dispersed among the White Russians.
Despite his early successes, Zhang's forces were overrun at Kulja and Chuguchak, and he committed suicide after the battle at Muzart Pass to avoid capture.
Even though the Soviets were superior to the 36th Division in both manpower and technology, they were held off for weeks and took severe casualties. The 36th Division managed to halt the Soviet forces from supplying Sheng with military equipment. Chinese Muslim troops led by Ma Shih-ming managed to hold off the superior Red Army forces armed with machine guns, tanks, and planes for about 30 days.
Ma Hushan, Deputy Divisional Commander of the 36th division, became well known for victories over Russian forces during the invasion.
At this point, Chiang Kai-shek was ready to send Huang Shaohong and his expeditionary force which he assembled to assist Ma Zhongying against Sheng, but when Chiang heard about the Soviet invasion, he decided to withdraw to avoid an international incident if his troops directly engaged the Soviets.
During the Islamic rebellion in Xinjiang In August 1937 , the Soviet Red Army sent 5000 troops, backed by an air unit and an armored regiment into Xinjiang at the request of Sheng Shicai ,the aircraft assisted the provincial forces by dropping bombs, including some containing mustard gas,On October 15th the Soviets bombed the city of Hotan, which resulted in 2,000 casualties.
Winter War (1939–1940)
On 30 November 1939, the Soviet Union invaded Finland, three months after the outbreak of World War II, and ended three and a half months later with the Moscow Peace Treaty on 13 March 1940. The League of Nations deemed the attack illegal and expelled the Soviet Union from the organisation.
The conflict began after the Soviets sought to obtain some Finnish territory, demanding among other concessions that Finland cede substantial border territories in exchange for land elsewhere, claiming security reasons—primarily the protection of Leningrad, 32 km (20 mi) from the Finnish border. Finland refused, so the USSR invaded the country. Many sources conclude that the Soviet Union had intended to conquer all of Finland, and use the establishment of the puppet Finnish Communist government and the Molotov–Ribbentrop Pact's secret protocols as evidence of this, while other sources argue against the idea of the full Soviet conquest. Finland repelled Soviet attacks for more than two months and inflicted substantial losses on the invaders while temperatures ranged as low as −43 °C (−45 °F). After the Soviet military reorganised and adopted different tactics, they renewed their offensive in February and overcame Finnish defences.
Hostilities ceased in March 1940 with the signing of the Moscow Peace Treaty. Finland ceded 11 percent of its territory representing 30 percent of its economy to the Soviet Union. Soviet losses were heavy, and the country's international reputation suffered. Soviet gains exceeded their pre-war demands and the USSR received substantial territory along Lake Ladoga and in northern Finland. Finland retained its sovereignty and enhanced its international reputation. The poor performance of the Red Army encouraged Adolf Hitler to think that an attack on the Soviet Union would be successful and confirmed negative Western opinions of the Soviet military. After 15 months of Interim Peace, in June 1941, Nazi Germany commenced Operation Barbarossa and the Soviet-Finnish theater of World War II, also known as the Continuation War, flared up again.
World War II (1939–1945)
The Soviet Union policy during World War II was neutrality until August 1939, followed by friendly relations with Germany in order to carve up Eastern Europe. The USSR helped supply oil and munitions to Germany as its armies rolled across Western Europe in May–June 1940. Despite repeated warnings, Stalin refused to believe that Hitler was planning an all-out war on the USSR. Stalin was stunned and temporarily helpless when Hitler invaded in June 1941. Stalin quickly came to terms with Britain and the United States, cemented through a series of summit meetings. The U.S. and Britain supplied war materials in large quantity through Lend Lease. There was some coordination of military action, especially in summer 1944.William Hardy McNeill, America, Britain, and Russia: Their Co-Operation and Conflict, 1941–1946 (1953)Richard J. Overy, The Dictators: Hitler's Germany and Stalin's Russia (2004)
In 1944–1945, the Red Army completely or partially occupied Romania, Bulgaria, Hungary, Yugoslavia, Poland, Czechoslovakia, Austria, Denmark, Finland, and Norway.Edele, M. (2015). Soviet liberations and occupations, 1939–1949. In R. Bosworth & J. Maiolo (Eds.), The Cambridge History of the Second World War (The Cambridge History of the Second World War, pp. 487-508). Cambridge: Cambridge University Press. doi:10.1017/CHO9781139524377.024
As agreed with the Allies at the Tehran Conference in November 1943 and the Yalta Conference in February 1945, the Soviet Union entered World War II's Pacific Theater within three months of the end of the war in Europe. The invasion began on 9 August 1945, exactly three months after the German surrender on 8 May (9 May, 0:43 Moscow time). Although the commencement of the invasion fell between the American atomic bombing of Hiroshima, on 6 August, and only hours before the Nagasaki bombing on 9 August, the timing of the invasion had been planned well in advance and was determined by the timing of the agreements at Tehran and Yalta, the long-term buildup of Soviet forces in the Far East since Tehran, and the date of the German surrender some three months earlier; on 3 August, Marshal Vasilevsky reported to Premier Joseph Stalin that, if necessary, he could attack on the morning of 5 August. At 11pm Trans-Baikal (UTC+10) time on 8 August 1945, Soviet foreign minister Vyacheslav Molotov informed Japanese ambassador Naotake Satō that the Soviet Union had declared war on Japan, and that from 9 August the Soviet government would consider itself to be at war with Japan."Soviet Declaration of War on Japan", 8 August 1945. (Avalon Project at Yale University)
Cold War
Korean War (1950–1953)
Though not officially belligerent during the Korean War (1950–1953), the Soviet Union played a significant, covert role in the conflict; it provided material and medical services, as well as Soviet pilots and aircraft, most notably MiG-15 fighter jets, to aid the North Korean-Chinese forces against the United Nations forces. The Soviets claimed 510 UN aircraft shot down in just the first year of the war and a total of 1,300 during the entire war while losing only 345 of their own.
Hungarian Revolution of 1956
After Stalinist Hungarian dictator Mátyás Rákosi was replaced by Imre Nagy following Stalin's death and Polish reformist Władysław Gomułka was able to enact some reformist requests, large numbers of protesting Hungarians compiled a list of demands,Internet Modern History Sourcebook: Resolution by students of the Building Industry Technological University: Sixteen Political, Economic, and Ideological Points, Budapest, 22 October 1956 Retrieved 22 October 2006 including free secret-ballot elections, independent tribunals, and inquiries into Stalin and Rákosi Hungarian activities. Under the orders of Soviet defense minister Georgy Zhukov, Soviet tanks entered Budapest.UN General Assembly Special Committee on the Problem of Hungary (1957) Protester attacks at the Parliament forced the collapse of the Soviet-backed government.UN General Assembly Special Committee on the Problem of Hungary (1957)
The new government that came to power during the revolution formally disbanded the Hungarian secret police, declared its intention to withdraw from the Warsaw Pact and pledged to re-establish free elections. The Soviet Politburo thereafter moved to crush the revolution with a large Soviet force invading Budapest and other regions of the country.UN General Assembly Special Committee on the Problem of Hungary (1957) Approximately 200,000 Hungarians fled Hungary, some 26,000 Hungarians were put on trial by the new Soviet-installed János Kádár government and, of those, 13,000 were imprisoned. Imre Nagy was executed, along with Pál Maléter and Miklós Gimes, after secret trials in June 1958. By January 1957, the Hungarian government had suppressed all public opposition. These Hungarian government's violent oppressive actions alienated many Western Marxists, yet strengthened communist control in all the European communist states, cultivating the perception that communism was both irreversible and monolithic.
Invasion of Czechoslovakia (1968)