As a consequence of the First and Second Vienna Awards, Košice was ceded to Hungary. During the German occupation of Hungary towards the end of World War II, approximately 10,000 Jews were deported by the Arrow Cross Party and the Nazis and killed in Auschwitz. The ethnic makeup of the town was dramatically changed by the persecution of the town's large Hungarian majority, population exchanges between Hungary and Slovakia and Slovakization and by mass migration of Slovaks into newly-built communist-block-microdistricts, which increased the population of Košice four times by 1989 and made it the fastest growing city in Czechoslovakia.