and other wealth transfers from occupied Europe, including two-thirds of the gross domestic product of Belgium and the Netherlands. The regime used violence and economic pressure to encourage Jews to voluntarily leave the country. Hundreds of camps of varying size and function were created by the end of the war. Nazi Germany: A New History. After the successful Battle of Smolensk in September 1941, Hitler ordered Army Group Centre to halt its advance to Moscow and temporarily divert its Panzer groups to aid in the encirclement of Leningrad and Kiev. Reinhard Heydrich, chief of the Sicherheitspolizei (SiPo; Security Police) and Sicherheitsdienst (SD; Security Service ordered on 21 September that Polish Jews should be rounded up and concentrated into cities with good rail links. The plot, part of Operation Valkyrie, involved Claus von Stauffenberg planting a bomb in the conference room at Wolf's Lair at Rastenburg. To determine who should be killed, Himmler created the Volksliste, a system of classification of people deemed to be of German blood. In Germany, rations were cut in 1942. Archived from the original on 28 September 2017. "Personelle Verluste der deutschen Bevölkerung durch Flucht und Vertreibung". Hitler's refusal to admit defeat led to massive destruction of German infrastructure and additional war-related deaths in the closing months of the war.