In July 1944 the Polish communists , working in close cooperation with Stalin and other Soviet leaders , established and declared in liberated Lublin a provisional executive quasi-government of Poland , which they called the Polish Committee of National Liberation ( PKWN ) . In the PKWN Manifesto issued at that time , the PKWN claimed its authority in Poland and promised post-war reconstruction as well as land reform . The KRN and the PKWN were established when the Polish government-in-exile in London was the internationally recognized government of Poland . By the end of 1944 , the PKWN was replaced with the Provisional Government of the Republic of Poland , recognized by the Soviet Union , with which it signed in April 1945 a 20-year friendship , alliance and cooperation treaty . As a result of the Yalta Conference Allied determinations , the Provisional Government was converted to a formally coalition Provisional Government of National Unity ( TRJN ) in June 1945 . The Polish government-in-exile was excluded from participation and the PPR ended up controlling the new government , which was soon recognized by the United States , the United Kingdom , and other countries . Establishment of a permanent government was conditioned on national elections being held , as mandated by the Allies . In the meantime the PPR engaged in a massive program of rebuilding the country and its industry , in combating and containing the various forms and manifestations of opposition to its rule , but also in manipulating the election preparation process to ensure the party 's lasting domination
Yalta Conference
Yalta Conference
Polish Workers' Party