The massacres of Poles in Volhynia and Eastern Galicia were carried out in German-occupied Poland by the Ukrainian Insurgent Army (UPA), with the support of parts of the local Ukrainian population, against the Polish minority in Volhynia, Eastern Galicia, parts of Polesia, and the Lublin region from 1943 to 1945. The UPA's actions resulted in up to 100,000 Polish deaths.
The peak of the massacres took place in July and August 1943. These killings were exceptionally brutal, and most of the victims were women and children. Other victims of the massacres included several hundred Armenians, Jews, Russians, Czechs, Georgians, and Ukrainians who were part of Polish families or opposed the UPA and impeded the massacres by hiding Polish escapees.
The killings were an attempt at ethnic cleansing to prevent the post-war Polish state from asserting its sovereignty over Ukrainian-majority areas that had been part of the pre-war Polish state. The decision to force the Polish population to leave areas that the Banderite faction of the Organization of Ukrainian Nationalists (OUN-B) considered to be Ukrainian took place at a meeting of military referents in the autumn of 1942, and plans were made to liquidate Polish-community leaders and any of the Polish community who resisted. Local UPA commanders in Volhynia began attacking the Polish population, committing massacres in numerous villages.
Encountering resistance, the UPA commander in Volhynia, Dmytro Klyachkivsky ("Klym Savur"), issued an order in June 1943 for the "general physical liquidation of the entire Polish population". The largest wave of attacks took place in July and August 1943, the assaults in Volhynia continuing until the spring of 1944, when the Red Army arrived in Volhynia and the Polish underground, which had organized Polish self-defense, formed the 27th AK Infantry Division. Approximately 50,000–60,000 Poles died as a result of the massacres in Volhynia, while up to 2,000–3,000 Ukrainians died as a result of Polish retaliatory actions.
At the Third Supreme Assembly of the OUN in August 1943, Mykola Lebed criticized the Ukrainian Insurgent Army's actions in Volhynia as "banditry". The majority of delegates disagreed with his assessment, and the Supreme Assembly decided to extend the anti-Polish operation into Galicia. However, it took a different course: by the end of 1943, it was limited to killing leaders of the Polish community and exhorting Poles to flee to the west under threat of looming genocide.
In March 1944, the UPA command, headed by Roman Shukhevych, issued an order to drive Poles out of Eastern Galicia, first with warnings and then by raiding villages, murdering men, and burning buildings. A similar order was issued by the UPA commander in Eastern Galicia, Vasyl Sydor ("Shelest"). This order was often disobeyed and entire villages were slaughtered. In Eastern Galicia between 1943 and 1946, OUN-B and UPA killed 20,000–25,000 Poles. 1,000–2,000 Ukrainians were killed by the Polish underground. Some Ukrainian religious authorities, institutions, and leaders protested the slayings of Polish civilians during the 1943–1944 events, but to little effect.
In 2008, Poland's Parliament adopted a resolution calling UPA's crimes against Poles "crimes bearing the hallmarks of genocide". In 2013 it adopted a resolution calling them "ethnic cleansing with the hallmarks of genocide". On 22 July 2016, Poland's Sejm established 11 July as a National Day of Remembrance for the Victims of Genocide committed by Ukrainian nationalists against citizens of the Second Polish Republic. This characterization is disputed by Ukraine and by some non-Polish historians, who characterize it instead as ethnic cleansing.
Interwar period in Second Polish Republic
The recreated Polish state covered large territories inhabited by Ukrainians, while the Ukrainian movement failed to achieve independence. According to the Polish census of 1931, in Eastern Galicia, the Ukrainian language was spoken by 52% of the inhabitants, Polish by 40% and Yiddish by 7%. In Wołyn (Volhynia), Ukrainian was spoken by 68% of the inhabitants, Polish by 17%, Yiddish by 10%, German by 2%, Czech by 2% and Russian by 1%.
In 1920, exiled Ukrainian officers, mostly former Sich Riflemen and veterans of Polish–Ukrainian War, founded the Ukrainian Military Organization (UVO), an underground military organization with the goal of continuing the armed struggle for independent Ukraine. As soon as the second half of 1922, UVO organized a wave of sabotage actions and assassination attempts on Polish officials and moderate Ukrainian activists. In 1929, the Organization of Ukrainian Nationalists (OUN) was formed in Vienna, Austria, and was the result of a union between several radical nationalist and extreme right-wing organisations with UVO. Members of the organization carried out several acts of terror and assassinations in Poland, but it was still rather fringe movement, condemned for its violence by figures from mainstream Ukrainian society such as the head of the Ukrainian Greek Catholic Church, Andriy Sheptytsky. The most popular political party among Ukrainians was in fact the Ukrainian National Democratic Alliance (UNDO), which was opposed to Polish rule but called for peaceful and democratic means to achieve independence from Poland.
By the beginning of the Second World War, the membership of OUN had risen to 20,000 active members, and the number of supporters was many times as many.
Polish policy towards Ukrainian minority
The policy of the Polish authorities towards the Ukrainian minority was changeable throughout the interwar period, varying between attempts at assimilation, conciliation and a policy of repression.
For example, in 1930 a terror campaign and civil unrest in the Galician countryside resulted in Polish police exacting a policy of collective responsibility on local Ukrainians in an effort to "pacify" the region. Ukrainian parliamentarians were placed under house arrest to prevent them from participating in elections, with their constituents terrorized into voting for Polish candidates. Beginning in 1937, the Polish government in Volhynia initiated an active campaign to use religion as a tool for Polonization and to convert the Orthodox population to Roman Catholicism. Over 190 Orthodox churches were destroyed and 150 converted to Roman Catholic churches.
On the other hand just before the war, Volhynia was "the site of one of eastern Europe's most ambitious policies of toleration". Through supporting Ukrainian culture and religious autonomy and the Ukrainization of the Orthodox Church, the Sanacja regime wanted to achieve Ukrainian loyalty to the Polish state and to minimise Soviet influences in the borderline region. That approach was gradually abandoned after Józef Piłsudski's death in 1935. Practically all government and administrative positions, including the police, were assigned to Poles.
Harsh policies implemented by the Second Polish Republic were often a response to OUN-B violence, but contributed to a further deterioration of relations between the two ethnic groups. Between 1921 and 1938, Polish colonists and war veterans were encouraged to settle in the Volhynian and Galician countryside; their number reached 17,700 in Volhynia in 3,500 new settlements by 1939. Between 1934 and 1938, a series of violent and sometimes-deadly attacks against Ukrainians were carried out in other parts of Poland. Volhynia was a place of increasingly violent conflict, with Polish police on one side and Western Ukrainian communists supported by many dissatisfied Ukrainian peasants on the other. The communists organized strikes, killed at least 31 suspected police informers in 1935–1936, and assassinated local Ukrainian officials for "collaboration" with the Polish government. The police conducted mass arrests, reported the killing of 18 communists in 1935, and killed at least 31 people in gunfights and during arrest attempts in 1936.
Ukrainian diversion in September 1939