As World War II continued, Ribbentrop's once-friendly relations with the SS became increasingly strained. In January 1941, the nadir of the relations between the SS and the Foreign Office was reached when the Iron Guard attempted a coup in Romania. Ribbentrop supported Marshal Ion Antonescu's government and Himmler supported the Iron Guard. In the aftermath of the failed coup in Bucharest, the Foreign Office assembled evidence that the SD had backed the coup, which led Ribbentrop to restrict sharply the powers of the SD police attachés. Since October 1939 they had operated largely independently of the German embassies at which they had been stationed. In the spring of 1941, Ribbentrop appointed an assemblage of SA men to German embassies in eastern Europe, with Manfred von Killinger dispatched to Romania, Siegfried Kasche to Croatia, Adolf Beckerle to Bulgaria, Dietrich von Jagow to Hungary, and Hans Ludin to Slovakia. The major qualifications of all these men, none of whom had previously held a diplomatic position before, were that they were close friends of Luther and helped to enable a split in the SS (the traditional rivalry between the SS and SA was still running strong).