Ragusa, Yugoslavia, The Italian army entering the city, 18/04/1941.
In the Balkans (Yugoslavia and Greece) German forces were supplemented by sizable Italian forces and by equally strong Croatian and Bosnian collaborationist contingents (about eight to ten divisions' worth). This increased the number of occupying troops to about the same as those in France. Despite these additional forces, the Balkans were the most restless area in the Nazi empire, and about 24,000 German troops died there during the war, plus many more Italians and pro-Axis locals (who also kept large parts of the Balkans relatively pro-German and quiet). In contrast, only about 12,000 Germans were killed during the North African campaign.
The Germans invaded Yugoslavia in early 1941, but Italians (who had attacked Albania in 1939) comprised most of the occupation troops until 1943, abetted by locally recruited Croat and Bosnian collaborators. A Resistance formed immediately, but because of the multicultural composition of Yugoslavia, and the enmity between Communists and monarchists, there was more fighting between partisans than with the occupying Italians.
The Invasion of Yugoslavia (code-name Directive 25 or Operation 25) was the Axis powers' attack on the Kingdom of Yugoslavia which began on 6 April 1941 during World War II. The invasion ended with the unconditional surrender of the Royal Yugoslav Army on 17 April 1941, the annexation and occupation of the region by the Axis powers and the creation of the Independent State of Croatia (Nezavisna Država Hrvatska, or NDH).
The Italian Second Army crossed the border soon after the Germans. They faced the Yugoslavian Seventh Army. The Italians encountered limited resistance and occupied parts of Slovenia, Croatia, and the coast of Dalmatia. In addition to the Second Army, Italy had four divisions of the Ninth Army on the Yugoslavian border with Albania. These formations were so situated against a Yugoslav offensive on that front. Around 300 Ustaše volunteers under the command of Ante Pavelic accompanied the Italian Second Army during the invasion; about the same number of Ustaše were attached to the German Army and other Axis allies.
The Independent State of Croatia was founded on 10 April 1941, after the invasion of Yugoslavia by the Axis powers. The state was technically a monarchy and Italian protectorate from the signing of the Rome agreements on 19 May 1941 until the Italian capitulation on 8 September 1943; but the king-designate, the Prince Aimone of Savoy-Aosta, refused to assume the kingship in opposition to the Italian annexation of the Croat-populated Yugoslav region of Dalmatia.
After Italy left the war in 1943, German troops took over the occupation. The partisans grabbed many of the Italians' weapons, and many anti-Fascist Italians even joined the partisans: One whole division more or less went over to them intact. While the Italians had usually been relatively easygoing during their occupation, the Germans were a lot tougher. Many of the non-Communist partisans collaborated with the Italians, and then with the Germans, to gain advantage over the Communist groups. Moreover, the Communist partisans were largely Serbs, while the monarchists were largely Croats. The other ethnic groups in Yugoslavia also tended to take sides against each other rather than against the occupying army. The Germans took advantage of this; to the extent that they raised two SS divisions comprised of Muslim Yugoslavs and then turned them loose on Christian civilians and partisans. Still, the partisans were a tough bunch and the Germans managed to assist the guerrillas by butchering suspected partisan sympathizers. This turned more of the population, and partisans, against the Germans. By this time, the Allies realized that, although they had been sending most of their aid to the non-Communist partisans, it was the Communist partisans led by Josip Broz (Tito) who were most energetically fighting the Germans. So by late 1943, the Allies got behind Tito and his Communist partisans. Throughout 1944, the partisans became stronger and stronger, and eventually, the Yugoslavs earned the distinction of being the only partisan army to liberate its own country without the aid of Allied troops. The Yugoslav partisans were even able to keep the Red Army out of the country. Meanwhile, by the end of the war, the non-Communist groups in the country were disarmed (and many killed) and a Communist government set up.