Axis occupation of Serbia

During World War II, several provinces of the Kingdom of Yugoslavia corresponding to the modern-day state of Serbia were occupied by the Axis Powers from 1941 to 1944. Most of the area was occupied by the Wehrmacht and was organized as separate territory under control of the German Military Administration in Serbia. Other parts of modern Serbia that were not included in the German-administered territory were occupied and annexed by neighboring Axis countries: Syrmia was occupied and annexed by the Independent State of Croatia, Bačka was occupied and annexed by Hungary, southeastern Serbia was occupied and annexed by Bulgaria, and southwestern Serbia was occupied and annexed by Italy and included in the Italian protectorates of Albania and Montenegro.

The area under control of the German Military Administration in Serbia was initially occupied by the Germans. It was later occupied mostly by Bulgarian troops, but remained under German military authority. On stamps and coins this territory was referred to as Serbia, and, according to Professor Paul N. Hehn, its official name was the Territory of the Military Commander in Serbia. This territory had two successive Serbian puppet governments which were under the control of the German military authorities. The first short-lived puppet government was known as the Commissioner Government and was led by Milan Aćimović. The second puppet government was known as the Government of National Salvation and was led by Milan Nedić.

...
Wikipedia