days. The SS took one of its most decisive steps in eliminating its competition for command of security within Germany and established itself firmly in the Nazi hierarchy, making the SS and its intelligence organ, the SD, responsible only to the Führer. The purge became known as the Night of the Long Knives, with up to 200 people killed in the action. Moreover, the brutal crushing of the SA and its leadership sent a clear message to everyone that opposition to Hitler's regime could be fatal. It struck fear across the Nazi leadership as to the tangible concern of the reach and influence of Himmler's intelligence collection and policing powers. SD and Austria During the autumn of 1937, Hitler secured Mussolini's support to annex Austria (Mussolini was originally apprehensive of the Nazi takeover of Austria) and informed his generals of his intentions to invade both Austria and Czechoslovakia. Getting Mussolini to approve political intrigue against Austria was a major accomplishment, as the Italian Duce had expressed great concern previously in the wake of an Austrian SS unit's attempt to stage a coup not more than three weeks after the Röhm affair, an episode that embarrassed the SS, enraged Hitler, and ended in the assassination of Austrian Chancellor Engelbert Dollfuss on 25 July 1934. Nonetheless, to facilitate the incorporation of Austria into the greater Reich, the SD and Gestapo went to work arresting people immediately, using lists compiled by Heydrich. Heydrich's SD and Austrian SS members received financing from Berlin to harass Austrian Chancellor von Schuschnigg's government all throughout 1937. One section of the SD that was nothing more than a front for subversive activities against Austria ironically promoted "German-Austrian peace". Throughout the events leading to the Anschluß and even after the Nazis marched into Austria on 12 March 1938, Heydrich – convinced that only his SD could pull off a peaceful union between the two German-speaking nations – organized demonstrations, conducted clandestine operations, ordered terror attacks, distributed propaganda materials, encouraged the intimidation of opponents, and had his SS and SD personnel round-up prominent anti-Nazis, most of whom ended up in Mauthausen concentration camp The coordinated efforts of the SiPo and Heydrich's SD during the first days of the Anschluß effectively eliminated all forms of possible political, military and economic resistance within Austria. Once the annexation became official, the Austrian police were immediately subordinated to Heydrich's SD, the SS and Gestapo.