Yugoslav government - in - exile The Yugoslav government in exile was the official government of Yugoslavia , headed by King Peter II , which evacuated from Belgrade in April 1941 , after the German invasion of the country , first to Greece , then Palestine , then to Cairo in Egypt and finally , in June 1941 , to the United Kingdom . History . Fearing an invasion by the Axis Powers , Regent Prince Paul signed the Tripartite Pact on 25 March 1941 , pledging cooperation with the Axis . Massive [ anti - Axis ] demonstrations followed in Belgrade . On 27 March , the regime of Prince Paul was overthrown by a military coup d ' état with British support . The 17 - year - old Peter II was declared to be of age and placed in power . General Dušan Simović became his Prime Minister . The Kingdom of Yugoslavia withdrew its support for the Axis " de facto " without formally renouncing the Tripartite Pact . Although the new rulers opposed Nazi Germany , they also feared that if German dictator Adolf Hitler attacked Yugoslavia , the United Kingdom was not in any real position to help . Regardless of this , on 6 April 1941 , the German armed forces ( " Wehrmacht " ) launched the invasion of the Kingdom of Yugoslavia and quickly conquered it . The royal family , including Prince Paul , escaped abroad and were interned by the British in Kenya . The Kingdom of Yugoslavia was soon divided by the Axis into several entities . Germany , Italy , Hungary , and Bulgaria annexed some border areas outright . A Greater Germany was expanded to include most of Slovenia . Italy added the Governorship of Dalmatia and more than a third of western Slovenia to the Italian Empire . An expanded Croatia was recognized by the Axis as the Independent State of Croatia ( " Nezavisna Država Hrvatska " , NDH ) . On paper , the NDH was a kingdom and the 4th Duke of Aosta was crowned as King Tomislav II of Croatia . The rump Serbian territory became a military administration of Germany run by military governors and a Serb civil government led by Milan Nedić . Nedić attempted to gain German recognition of Serbia as a successor state to Yugoslavia and claimed King Peter II as Serbia ' s monarch . Puppet state s were also set up in Montenegro and southern Yugoslavia . Hungary occupied several northern regions . King Peter II , who had escaped into exile , was still recognized as King of the whole state of Yugoslavia by the Allies . From 13 May 1941 , the largely Serbian " Yugoslav Army of the Fatherland " ( " Jugoslovenska vojska u otadžbini " , or JVUO , or Četniks ) resisted the Axis occupation of Yugoslavia . This anti - German and anti - communist resistance movement was commanded by Royalist General Draža Mihailović . For a long time , the Četniks were supported by the British , the United States , and the Yugoslavian royal government in exile of King Peter II . However , over the course of the war , effective power changed to the hands of Josip Broz Tito ' s Communist Partisans . In 1943 , Tito proclaimed the creation of the Democratic Federative Yugoslavia ( " Demokratska federativna Jugoslavija " ) . The Allies gradually recognized Tito ' s forces as the stronger opposition forces to the German occupation . They began to send most of their aid to Tito ' s Partisans , rather than to the Royalist Četniks . On 16 June 1944 , the Tito – Šubašić agreement was signed which merged the " de facto " and the " de jure " government of Yugoslavia . During the exile King Peter II was educated at Cambridge University , served in the Royal Air Force and married Princess Alexandra of Greece and Denmark who was the only child of the late King Alexander I of Greece and Princess Aspasia of Greece and Denmark .