The Mačva operation or Cleaning Up the Sava Crescent (, ) was a German military operation during the uprising in the German-occupied territory of Serbia. This operation was in some contemporary German documents and in some works was referred to as operation Cleansing of Mačva. The aim of operation was the destruction of rebel forces of Chetniks and Partisans in the region of Mačva and their headquarters on the mountain Cer-Iverak and committing mass massacres of the local population with the intention to set a "terrifying example" to the rest of the population of Serbia. The commander of the German forces was the newly appointed military commander of the occupied territory Franz Böhme who brought the 342nd Infantry Division with 12,000 soldiers of younger age from France to western Serbia to support poorly equipped and undertrained soldiers of older age in the 718th Division and parts of the 704th Division. The operation started on 24 September 1941 when 342nd Infantry Division crossed river Sava and attacked rebel forces besieging Šabac who retreated toward Cer-Iverak mountain. The German forces, supported by the Ustaše Militia, organized massive massacres of the civilian population and killed about 6,000 and imprisoned more than 21,000 civilians. The operation ended on 9 October 1941 with the failure of Axis forces to destroy rebels and their headquarters because the rebel forces were forced to retreat to the south after suffering casualties of 742 men. To complete the aim of this operation and prepare preconditions to suppress the uprising in the rest of Serbia, Böhme ordered another military operation (Cer-Iverak) and series of other operations that eventually crushed the Uprising in Serbia, with total number of about 4,000 rebels killed during the uprising and about 35,000 civilians killed in reprisals. Background At the beginning of the Uprising in Serbia the Axis forces were unable to suppress the uprising because of the engagement of the Wehrmacht at Eastern Front. That is why the joint forces of the Yugoslav Army and the Yugoslav communist party managed to capture substantial territory in the Western part of the German-occupied Serbia. On 16 September 1941, to secure the supply routes of his troops through Western Serbia, Hitler ordered Wilhelm List to suppress the uprising in Serbia reinforce the troops in Serbia. On the same day, Hitler appointed Franz Böhme, who at that time was a commander of the 18th Army Corps in Greece, on