In 1936, he became a director of the "Kulturbund Deutscher Juden" (JKB) in Berlin, a German-Jewish cultural organisation backed by the Nazi Propaganda Ministry of Joseph Goebbels, which allowed Jewish artists to perform for Jewish audiences. He also conducted in Gothenburg between 1936 and 1938. The Nazis imprisoned him from 1939 to 1940. When the JKB was dissolved in 1941, he was deported to Auschwitz, but Wilhelm Furtwängler's wife Zitla secured his release. He was then sent to Sachsenhausen and ended up in Belsen concentration camp in 1945. While at Auschwitz, he suffered a broken shoulder-blade, which inhibited his gestures as a conductor in later life. The effects of this injury on his conducting style can be seen in a DVD of him conducting the finale of the Brahms Violin Concerto with David Oistrakh in May 1958.