Ukrainian Insurgent Army war against Russian occupation
The Ukrainian anti-Soviet armed resistance was an armed struggle waged by the Ukrainian Insurgent Army (UPA) against Soviet rule from 1941 to 1960 in the western regions of the Ukrainian SSR, eastern voivodeships of Poland, and southwestern regions of the Byelorussian SSR. With the restoration of Soviet rule of Ukraine in 1944, the UPA conducted large-scale hostilities against the government, and then, due to heavy losses, gradually turned to guerrilla warfare. From 1944 to 1956, about 155,000 insurgents were killed by Soviet troops and Soviet-state security agencies. Those killed included  key Ukrainian Insurgent Army leaders: Roman Shukhevych, Dmytro Klyachkivsky, Oleksandr Lutsky, Petro Oliynyk, among others. The interior security agencies of the Soviet Union (NKVD until 1946, MVD starting in 1946) formed the basis of the forces that fought against the Ukrainian national liberation movement in the 1940s and 1950s. They used some fighter battalions from the local population that cooperated with the Communists. In 1956 the Soviet troops ultimately defeated the UPA. Background. The Russian occupation of 1939-1941 was terrible for local Ukrainians, so the Soviets did not gain much public support. Soviet units were going to destroy UPA  units and create their own network of agents in the nationalist underground to dismantle it from within. The first insurgent troops to fight the Red Army and Soviet partisans was Ukrainian People's Revolutionary Army (a different organization than the Ukrainian Insurgent Army) under command of Taras Bulba-Borovets. This army was loyal to Government of the Ukrainian People's Republic in exile. On June 20, 1940, by order of the President of the Ukrainian People's Republic in exile Andriy Livytsky, he was to form and lead the Ukrainian Insurgent Army "Poliska Sich". When the Germans invaded the Soviet  Union in the 1941 Operation Barbarossa, the Soviets had approximately 150,000 prisoners, and in the haste of the Red Army to retreat they killed about two thirds of them These NKVD prisoner massacres served as pretext for a wave of killings by Ukrainian nationalists with the encouragement of Reinhard Heydrich's "Einsatzgruppen" Unlike in Western Europe, mass murders of Jews were carried out not in extermination camps but in mass shootings organized by their neighbors. In Czortków-Buchach in eastern Galicia, for example, several hundred Ukrainian auxiliaries, but only about 30 German policemen, killed about 60,000 Jews (95% of the  Jewish population), mostly between fall 1942 and summer 1943. Another militant group, the Ukrainian Insurgent Army (UPA), who were loyal to Organization of Ukrainian Nationalists, emerged in the winter of 1942-43. The UPA troops didn't support Ukrainian People's Republic. Conflict between two insurgent armies led to renaming one of them the Ukrainian People's Revolutionary Army on 20 July 1943. Later the name Ukrainian Insurgent Army was used by supporters of Organization of Ukrainian Nationalists. At first this group fought against Soviet partisans, who the Organization of Ukrainian Nationalists (OUN-B) called Red partisans and described as  agents of "Stalin and Sikorsky" and "the vanguard of Moscow imperialism." In Volhynia and Galicia, organizational and underground movement advances for Soviet partisans were particularly difficult due to the rapid occupation of the territory of Western Ukraine by Nazi forces. In the autumn and winter of 1943, Soviet state security agencies had to deal with nationalist organizations in eastern Ukraine. Underground groups emerged during the German occupation in Dnipropetrovsk, Zaporizhia, Poltava, Kyiv, Zhytomyr, and Stalin (now Donetsk) oblasts. In total, according to State Archive of the Russian Federation (GARF), as a result of the sale of intelligence materials, 26 such  groups with 226 participants were eliminated. At the beginning of 1944, the Red Army came to the UPA's areas of activity. In January–February 1944, it occupied a large part of Volhynia. The troops of the 1st Ukrainian Front, with the forces of the 13th and 60th armies, carried out the Rivne-Lutsk offensive, capturing these two regional centers on February 2. In the occupied territories, the Soviet authorities seized food, conscripted local Ukrainians en masse into the Red Army, and after a few days of training threw them on the front. The majority of party and state cadres  were foreigners from the USSR, who often behaved like conquerors in a conquered country, and treated the local Ukrainian population with contempt. There were also numerous examples of fraud, theft, and rape committed by Soviet soldiers. Support grew for the Ukrainian underground. By July 1943 the UPA had twenty thousand soldiers and in 1944, it reached a peak membership of 25-30 thousand guerrillas. To this must be added the militias of the Sluzhba Bezpeky, the OUN Security Council, and those belonging only to the OUN civic network, which existed in most Ukrainian towns and villages. The approach of the  Red Army forced UPA's to develop further strategy and tactics of war with occupiers. The command decided to cross the front line through the fighting Soviet order and exit to their rear areas. The group was ordered to leave the Vinnytsia and Kamianets-Podilskyi regions, where there were few forests, and retreat to Volhynia together with two parts of the army group. In the second half of January 1944, units of the Ukrainian Insurgent Army crossed the front in the Volhynia forest belt along the Sluch and Horyn rivers. At the very beginning of 1944, the UPA advocated that  some Ukrainians should not avoid a mobilization in the Red Army. But they would join it in order to disintegrate from within. However, as early as March 1944, the UPA urged young people to evade conscription into the Red Army. The III Extraordinary Congress of the Organization of Ukrainian Nationalists (OUN-B), decided to send UPA troops on raids deep into the USSR: eastern Ukraine, Belarus, and the Caucasus, raising nations to revolt against the USSR. Although the raids ended in complete failure, the Ukrainians did not to give up. They saw a chance for success at the beginning of  World War II and considered Britain and the United States allies. Their will to fight was strengthened by the widespread belief that the Soviet government would kill or, at best deport, everyone in Western Ukraine. The OUN leadership and the UPA command were convinced that the Russians were prepared to destroy all Ukrainians, basing this on the experience of the Great Famine of the 1930s, when five million people or more Soviet citizens starved to death between 1931 and 1934, 3.9 million of them Ukrainian. They believed that it was better to die in battle than to passively allow themselves  to be killed. OUN members tried to attract not only Ukrainians to the UPA but also members of other nationalities, especially military specialists from the encirclement and prisoners of war. Although there were national divisions in the UPA, this attempt also failed. The OUN-UPA invented a system of underground hideouts. These secret shelters were built in anticipation of the arrival of Soviet troops. They were dugouts with entrances masked by a stump or a box filled with earth in which a young tree was planted. Entrances were hidden under piles of garbage, haystacks, wells, kennels, and even graves. A  total of 10,000 hideouts were built during the UPA's existence. UPA from 1941 to 1943. Ukrainian People's Revolutionary Army defeated a Soviet force and captured Olevsk on 20 August 1941. In November 1941, the Nazis, with the help of the army and police, established administrative control over the territory. UPA units were partially disarmed and disbanded, and partially relocated illegally. However, even after that, the power of the occupation administration over the territory of Polissya was mostly limited to cities, railway stations and roads. The countryside turned into an arena of brutal confrontation between several guerrillas armies. During  the autumn and winter of 1942, Taras Bulba-Borovets negotiated with Soviet partisans and reached a "non-aggression" agreement, which lasted until February 1943. The maximum number of UPA units was approximately 3000-4000. Clashes of the Red Army with the UPA (early 1944). After the arrival of the Red Army, Ukrainian guerrilla units took action to hamper the emergence of communist local occupation authorities. Most of the open clashes ended in serious setbacks for the relatively poorly prepared UPA units. Therefore, to avoid fighting with regular troops, UPA units attacked mobilization points, liaison offices, and quartermasters. The UPA leadership  instructed its units to hold a welcome reception for the Red Army occupying the cities and villages of Western Ukraine, to lull their vigilance, and then to strike unexpected blows at their headquarters, bases, and some small units to replenish their stocks of weapons and products. According to the Rivne Regional Committee of the party, in January–February 1944 there were 56 UPA detachments, numbering from 100 to 600 people each. The total number was 10,600 fighters. In January–February 1944, Soviet sources in the Rivne region recorded 154 attacks on small units and individual soldiers, which killed 439 Red  Army soldiers.<ref name=Radjan>