Original sentence: , actively collaborated with the occupational forces.As the Germans and their allies began to lose ground to the anti-Nazi guerrillas in 1944, and started retiring to Albania, many hundreds of Chams followed them.During the Nazi occupation of Greece (1941-1944) many local Albanian-spoken inhabitants (see Cham Albanians), under an Axis-backed organisation called K.Muslim Cham units also played an active part in the Holocaust in Greece, including the round-up and expulsion to Auschwitz and Birkenau of the 2,000-strong Romaniote Greek-Jewish community of Ioannina in April 1944.These Albanian Cham units committed, alongside the Wehrmacht, a number of atrocities against their ethnically Greek fellow citizens, burning houses and villages, killing several hundred ethnic Greeks and forcing thousands others to flee their homes