More than two years after annexing Subcarpathian Rus, in the first ten days of August 1941, Hungarian authorities expelled about 18,000 Jews from Subcarpathian Rus into German-occupied Ukraine. Hungarian military units rounded the Jews up, loaded them into freight cars, and transported them to Korösmezo (Yasinya), near the prewar Hungarian-Polish border, and handed them over to German authorities.
German SS and police units forced the Jews, many of whom were still together as families, to march from Kolomyja (Kolomyya) to Kamenets-Podolsk (Kam'yanets'-Podil's'kyy) in the western Ukraine, and shot them there. Other than this incident, the Hungarian authorities did not kill Jews in Hungarian-annexed Slovakia or in Subcarpathian Rus prior to the German occupation, though several thousand of the 42,000 deaths of Hungarian Jews while serving in Hungarian Labor Battalions were natives of these regions.
On March 19, 1944, the Germans occupied Hungary, toppling the government of Miklós Kállay, which had resisted the deportation of the Hungarian Jews and installing the government of Döme Sztójay, which was prepared to move against the Hungarian Jews. By this time, more than 150,000 Jews who had been residents of Czechoslovakia in 1938 resided in Hungary.
Two months after the German occupation, in May, Hungarian authorities systematically deported around 140,000 Jews from southern Slovakia and Subcarpathian Rus to the border of the Government General. Once they had custody of the Hungarian Jews, German SS and police officials deported them to the Auschwitz-Birkenau killing center, where the SS killed the majority of them in the gas chambers.
A minority of Hungarian Jews arriving in Auschwitz were selected for forced labor and deployed either in the Auschwitz concentration camp complex or transferred west to concentration camps in Germany. Several thousand Jews managed to escape deportation by hiding in the mountains or fleeing to Romania. Possibly as many as 25,000 Jews from southern Slovakia and Subcarpathian Rus survived the war.
The Germans and their collaborators killed approximately 263,000 Jews who had resided on the territory of the Czechoslovak Republic in 1938.