second observation was that the entire German 1st Mountain Division had traveled from Russia by railway through Chetnik-controlled territory. British intercepts (ULTRA) of German message traffic confirmed Chetnik timidity. All in all, intelligence reports resulted in increased Allied interest in Yugoslavia air operations and shifted policy. In September 1943, at Churchill's request, Brigadier General Fitzroy Maclean was parachuted to Tito's headquarters near Drvar to serve as a permanent, formal liaison to the Partisans. While the Chetniks were still occasionally supplied, the Partisans received the bulk of all future support. Thus, after the Tehran Conference the Partisans received official recognition as the legitimate national liberation force by the Allies, who subsequently set up the RAF Balkan Air Force (under the influence and suggestion of Brigadier-General Fitzroy Maclean) with the aim to provide increased supplies and tactical air support for Marshal Tito's Partisan forces. During a meeting with Franklin D. Roosevelt and the Combined Chiefs of Staff of 24 November 1943, Winston Churchill pointed out that: Activities increase (1943–1945) With Allied air support (Operation Flotsam) and assistance from the Red Army, in the second half of 1944 the Partisans turned their attention to Serbia, which had seen relatively little fighting since the fall of the Republic of Užice in 1941. On 20 October, the Red Army and the Partisans liberated Belgrade in a joint operation known as the Belgrade Offensive. At the onset of winter, the Partisans effectively controlled the entire eastern half of Yugoslavia – Serbia, Vardar Macedonia and Montenegro, as well as the Dalmatian coast. In 1945, the Partisans, numbering over 800,000 strong defeated the Armed Forces of the Independent State of Croatia and the Wehrmacht, achieving a hard-fought breakthrough in the Syrmian front in late winter, taking Sarajevo in early April, and the rest of the NDH and Slovenia through mid-May. After taking Rijeka and Istria, which were part of Italy before the war, they beat the Allies to Trieste by two days. The "last battle of World War II in Europe", the Battle of Poljana, was fought between the Partisans and retreating Wehrmacht and quisling forces at Poljana, near Prevalje in Carinthia, on 14–15 May 1945. Overview by post-war republic Serbia The Axis invasion led to the division of Yugoslavia between the Axis powers and the Independent State of Croatia. The largest part of Serbia was organized into the Territory of the Military Commander in Serbia and as