The agreements of the Yalta and Tehran Conferences , signed by American President Roosevelt , Soviet Premier Joseph Stalin and British Prime Minister Churchill , determined the fates of the Cossacks who did not fight for the USSR , because many were POWs of the Nazis . Stalin obtained Allied agreement to the repatriation of every so-called " Soviet " citizen held prisoner because the Allied leaders feared that the Soviets either might delay or refuse repatriation of the Allied POWs whom the Red Army had liberated from Nazi POW camps
Yalta
Yalta Conference
Repatriation of Cossacks after World War II