Ukrainian Soviet Socialist Republic
Eventually, after the creation of the Communist Party (Bolshevik) of Ukraine in Moscow, a third Ukrainian Soviet government was formed on 21 December 1919 that initiated new hostilities against Ukrainian nationalists as they lost their military support from the defeated Central Powers. Eventually, the Red Army ended up controlling much of the Ukrainian territory after the Polish-Soviet Peace of Riga. On 30 December 1922, along with the Russian, Byelorussian, and Transcaucasian republics, the Ukrainian SSR was one of the founding members of the Union of Soviet Socialist Republics (USSR).
Hungarians in Ukraine
When the Soviet Army crossed the pre-1938 borders of Czechoslovakia in 1944, Soviet authorities refused to allow Czechoslovak governmental officials to resume control over the region, and in June 1945, President Edvard Beneš formally signed a treaty ceding the area to the Soviet Union. It was then incorporated into the Ukrainian SSR. After the break-up of the Soviet Union, it became part of independent Ukraine as the Zakarpattia Oblast.