The action was carried out by the Soviet-installed Polish communist authorities to remove material support to the Ukrainian Insurgent Army.

[1][2] The Ukrainian Insurgent Army continued its guerrilla activities until 1947 in Subcarpathian and Lublin Voivodeships with no hope for any peaceful resolution; Operation Vistula brought an end to the hostilities.

[3] In a period of three months beginning on 28 April 1947 and with Soviet approval and aid about 141,000 civilians residing around Bieszczady and Low Beskids were forcibly resettled to former German territories, ceded to Poland at the Yalta Conference at the end of World War II.

[3] It is sometimes assumed that the cause for Operation Vistula was the assassination on 28 March 1947 of the Polish communist General Karol Świerczewski in an ambush set up by the UPA.

[3] In the aftermath of the death of Karol Świerczewski, Lieutenant Colonel Wacław Kossowski, though concluding that the identity of the assailants responsible for Świerczewski's death was 'impossible to determine', nonetheless advised the Polish general staff on 11 April "As soon as possible, an Operational Group should be organized, which would elaborate a plan to include among other matters the complete extermination of the remnants of the Ukrainian population in the southeastern border region of Poland".

[9] On April 16, 1947, the Minister of Public Security (MBP) divisional general Stanisław Radkiewicz and Marshal Michał Rola-Żymierski, the Minister of National Defence, issued the operative and organization plan for an operation named Akcja Wschód ('Operation East') articulating the goal of the operation as "To solve the Ukrainian problem in Poland once and for all" and instructing the participants to "Conduct evacuation from the southern and eastern border region of all the people of Ukrainian descent...and settle them in the north-western territories of Poland in the highest possible degree of scattering...".

[1] The expellees were resettled over a wide area in the Northern and Western Territories assigned to Poland by the Potsdam Agreement including Warmia and Masuria.

[11] A principle of 'collective responsibility' was applied–all Ukrainians within the indicted area of Poland were deported regardless of political leanings, alliances and historical affiliations.

Mixed families, communities that did not support UPA, Lemkos returning from Red Army service, "even loyal party members trained in the Soviet Union, even communists who helped 'repatriate' Ukrainians in the previous wave, were forcible resettled".

Nationality was not decided by 'individual choice' but by religion, language and "frequently by the letter 'U' in the Kennkarte Polish citizens received from the Nazi occupation during the war".

[9] The Ukrainians were transported in compact cattle and box cars, sanitary conditions were poor and food supplies irregular, some deportees died during transit.

The final destination and degree of dispersal of groups was determined by the judgement of the intelligence officers, whose colleagues were waiting to receive their instruction in sealed envelopes at the end of the line.

Poland and the Soviet Ukraine conducted population exchanges resulting from bilateral agreements signed on 9 September 1944 and 16 August 1945.

[12] The expedited plan approved by Civil Security Minister Brigadier General Radkevych and Marshal Zhymerski instructed "Conduct evacuation from the Southern and Eastern border region of all the people of Ukrainian descent...and settle them in the north-western territories of Poland in the highest possible degree of scattering...".

[9] Ukrainians were faced with largely decrepit accommodations, as most habitable buildings in the 'recovered territories' had recently been moved into by newly repatriated Poles after the 1944 Polish-Soviet population transfers.

[1] The largest communities of Lemkos live in the villages Łosie, Krynica, Nowica, Zdynia, Gładyszów, Hańczowa, Zyndranowa, Uście Gorlickie, Bartne, Bielanka, and in the eastern part of Lemkovyna – Wysoczany, Mokre, Morochów, Szczawne, Kulaszne, Rzepedź, Turzańsk, Komańcza.