he could conduct late evening broadcasts. On 1 April 1941 Pavelić called for the liberation of Croatia. On 6 April 1941 the Axis invaded Yugoslavia from multiple directions, rapidly overwhelming the under-prepared Royal Yugoslav Army which capitulated 11 days later. The German operational plan included making 'political promises to the Croats' to increase internal discord. The Germans generally preferred to collaborate with non-fascists who were willing to work with them, and only placed out-and-out fascists in charge as a last resort. Croatia was no exception. The Nazis wanted any Croatian puppet government to have popular support, so that they could control their zone of occupation with minimal forces and exploit the available resources peacefully. The administration of Banovina Croatia had been under the control of an alliance of Vladko Maček's HSS and the mostly Croatian Serb Independent Democratic Party. Maček was very popular among Croats, had been vice-premier in the Yugoslav Cvetković government, was a supporter of Yugoslav accession to the Axis and had a ready made para-military force in the form of the HSS Croatian Peasant Defence. As a result, the Germans attempted to get Maček to proclaim an "independent Croatian state" and form a government. When he refused to cooperate, the Germans decided they had no alternative other than to support Pavelić, even though they considered that the Ustaše could not provide an assurance they could govern in the way the Germans wanted. It was estimated by the Germans that Pavelić had around 900 sworn Ustaše in Yugoslavia at the time of the invasion, and the Ustaše themselves considered that their supporters only numbered some 40,000. The Germans also considered Pavelić to be an Italian agent or "Mussolini's man", but considered that other senior Ustašas such as deputy leader () Slavko Kvaternik were sufficiently pro-German to ensure their interests would be supported by any regime led by Pavelić. On 10 April 1941, Kvaternik declared an Independent State of Croatia in the name of the Poglavnik Ante Pavelić via the Zagreb Radio Station. Kvaternik was acting on the orders of SS-Brigadeführer (Brigadier) Edmund Veesenmayer. The proclamation was viewed favourably by a significant portion of the population, particularly those living in Zagreb, western Herzegovina and Lika. The Croatian Peasant Defence, which had been infiltrated by the Ustaše, assisted by disarming Royal Yugoslav Army units and imposing some control. However, the Ustashe received limited support from ordinary Croats. The commander of