The Einsatzgruppen Operational Situation Reports (OSRs), or ERM for the German: Die Ereignismeldung UdSSR (plural: Ereignismeldungen), were dispatches of the Nazi death squads (Einsatzgruppen), which documented the progress of the Holocaust behind the German-Soviet frontier in the course of Operation Barbarossa, during World War II. The extant reports were sent between June 1941 and April 1942 to the Chief of the Security Police and the SD (German: Chef des Sicherheitspolizei und SD) in Berlin, from the occupied eastern territories including modern-day Poland, Belarus, Ukraine, Russia, Moldova, and the Baltic Countries. During the Nuremberg War Crimes Trials the originals were grouped according to year and month and catalogued using a consecutive numbering system, as listed in the below table.