The Ustaše gained German support for plans to eliminate the Serb population in Croatia. One plan involved an exchange in 1941 between Germany and the NDH, in which 20,000 Catholic Slovenes would be deported from German-held Slovenia and sent to the NDH where they would be assimilated as Croats. In exchange, 20,000 Serbs would be deported from the NDH and sent to the German-occupied territory of Serbia. On the meeting with Hitler on 6 June 1941 in Salzburg, Pavelić agreed to receive 175,000 deported Slovenes. The agreement provided that the number of Serbs deported from NDH to Serbia could exceed the number of Slovenes received by 30,000. During the talks, Hitler stressed the necessity and desirability of deportations of Slovenes and Serbs, and advised Pavelic that NDH, in order to become stable, should carry on ethnically intolerant policy for the next 50 years. The German occupation forces allowed the expulsion of Serbs to Serbia, but instead of sending the Slovenes to Croatia, they were also deported to Serbia. In total, about 300,000 Serbs had been deported or fled from the NDH to Serbia by the end of World War II.