The 5th Army was to be organized and mobilized on a geographic basis from the peacetime 5th Army District, which was divided into three divisional districts, each of which was subdivided into regimental regions. First countrywide mobilization in Yugoslavia commenced in September 1939 after the German invasion of Poland. Between two and four infantry regiments were raised in every divisional district, all cavalry regiments, most artillery divizions and Border Guard units were also raised. This mobilization was unsuccessful as the Yugoslav Army lacked military equipment, especially transport vehicles and animals. The mobilization method also proved to be ineffective and all units were demobilized after several months. Next mobilization in the 5th Army District commenced on 12 November 1940, two weeks after Italy invaded Greece. In the 5th Army District, the 5th Infantry Division "Šumadijska" and the 46th Infantry Division "Moravska" were to be completely mobilized while the 22nd Infantry Division "Ibarska", the 9th Infantry Division "Timočka", the 8th Infantry Division "Krajinska", and the 34th Infantry Division "Toplička" were to be partly mobilized. The Staff of the 5th Army District assessed mobilized units as "usable" but the units lacked transport vehicles and animals.