General Dusan Simovic and other anti-German officers overthrew the pro-Axis government in Yugoslavia, placing Regent Prince Paul with King Petar II and intending to back out of the Tripartite Pact. Upon hear the news, Adolf Hitler ordered an invasion of Yugoslavia; the German foreign ministry prepared messages to Hungary, Bulgaria, and Italy for them to join in the partition Yugoslavia. On the same day, 500 German military aircraft were dispatched for Bulgaria and Romania
