In 1941, SS leaders developed a plan to use Soviet POWs as slave labourers in concentration camps. But the camps received far fewer Soviets than expected, while most of those who did arrive died quickly. Looking for replacements, Himmler ordered mass deportations of Jews instead, as the following message to Camp SS manager Richard Glücks shows. Systematic deportations to Auschwitz began in late March 1942. Initially, they brought fewer Jews than anticipated: by the end of June, some 16,000 had arrived from France and Slovakia (not Germany, as Himmler had thought). Because they were earmarked for slave labour, the SS did not murder them on arrival. Still, most died within months, due to illness and violence.
Since Russian prisoners of war are not expected in the immediate future I shall be sending a large number of Jews and Jewesses who are being emigrated [sic] from Germany to the camps. During the next four weeks prepare to receive 100,000 male Jews and up to 50,000 female Jews in the KL [concentration camps]. During the next few weeks the concentration camps will be assigned major economic tasks and commissions. SS-Gruppenführer Pohl will provide you with detailed instructions.
Source: Institut für Zeitgeschichte, Fa 183, Bl. 61
Translation: Lesley Sharpe and Jeremy Noakes