Invasion of Yugoslavia (1941): The April War and Its Aftermath

The invasion of Yugoslavia, known in the region as the April War, was the attack on the Kingdom of Yugoslavia by Germany, Italy and Hungary that began on 6 April 1941. It opened with a heavy air raid on Belgrade and ended with the Yugoslav army’s surrender after only 12 days. The country was then partitioned, and occupation quickly gave rise to resistance, civil war and mass atrocities.

Background: the pact and the coup

By early 1941 Yugoslavia was surrounded by Axis states or their allies, and Germany was preparing to rescue Italy’s failing campaign in Greece. Under heavy pressure, the government of Prince Regent Paul and Prime Minister Dragiša Cvetković signed the Tripartite Pact in Vienna on 25 March 1941.

The decision was deeply unpopular, especially among Serbs. On 27 March a group of air force officers led by General Dušan Simović overthrew the government, declared the 17-year-old King Peter II of age and formed a new cabinet. Crowds celebrated in Belgrade’s streets, some chanting the slogan “better war than the pact”. Many Serbs saw the agreement as a humiliation, while the coup was received more coolly in Croatia and Slovenia, reflecting the national tensions that had troubled Yugoslavia since its creation in 1918. Although the new government did not formally leave the pact, Hitler ordered the same day that Yugoslavia be crushed militarily and as a state.

The campaign

At dawn on 6 April 1941 the Luftwaffe launched Operation Punishment, a series of heavy raids on Belgrade. Waves of bombers struck the city over two days, and the attack destroyed much of the Yugoslav air force on the ground. Large parts of the capital were destroyed, including the National Library with its collection of medieval manuscripts. Estimates of the dead range from about 1,500 to several thousand.

German armies attacked from Austria, Hungary, Romania and Bulgaria, and Italian forces advanced from the north-west and from Albania. Hungary joined the invasion on 11 April. The Yugoslav army of around a million men was poorly equipped, still mobilising and spread along long frontiers, and some Croatian units refused to fight for the Yugoslav state.

The Yugoslav high command had planned to defend the long northern frontier rather than withdraw to the mountainous interior, which left its divisions exposed to fast-moving German armour. German forces from Bulgaria pushed into southern Yugoslavia and cut it off from Greece, wrecking any hope of joint action with the Greek and British forces fighting there.

Resistance collapsed quickly. On 10 April German troops entered Zagreb, where the Ustaše, a Croatian fascist movement, proclaimed the Independent State of Croatia. Belgrade fell on 12–13 April. The king and government flew into exile, and on 17 April the army signed an unconditional surrender that took effect the next day. German losses were very light, while hundreds of thousands of Yugoslav soldiers were taken prisoner.

Partition and occupation

The victors divided the country:

• Germany annexed northern Slovenia and placed Serbia under military occupation.
• Italy annexed southern Slovenia and much of Dalmatia, and occupied Montenegro; Italian-ruled Albania received most of Kosovo and western parts of Macedonia.
• Hungary annexed the Bačka and other northern districts.
• Bulgaria took most of Vardar Macedonia and part of south-eastern Serbia.
• The Independent State of Croatia, led by Ante Pavelić, included Croatia, Bosnia and Herzegovina and parts of Serbia, under German and Italian influence.

The Ustaše regime began a campaign of terror against Serbs, Jews and Roma, including mass killings and camps such as Jasenovac. In occupied Serbia the Germans set up a collaborationist administration and, in the second half of 1941, murdered most of the country’s Jewish men in reprisal shootings.

Resistance and civil war

Hundreds of thousands of Yugoslav soldiers went into German captivity, though many non-Serbs were soon released, while Serbian prisoners were kept in camps in Germany for the rest of the war. Two main resistance movements emerged. Royalist officers under Colonel Draža Mihailović formed the Chetniks, based at Ravna Gora in Serbia from May 1941. After Germany invaded the Soviet Union in Operation Barbarossa, the Communist Party under Josip Broz Tito launched a Partisan uprising in July 1941.

The two movements soon fought each other as well as the occupiers. German reprisals against civilians were savage. Tito’s Partisans emerged victorious in 1945, establishing a Communist Yugoslavia that would later break with Moscow in the Tito–Stalin split.

Timeline

• 1941, 25 March: Yugoslavia signs the Tripartite Pact in Vienna.
• 1941, 27 March: Military coup in Belgrade; Peter II takes the throne.
• 1941, 6 April: Germany bombs Belgrade and invades Yugoslavia and Greece.
• 1941, 10 April: The Independent State of Croatia is proclaimed in Zagreb.
• 1941, 11 April: Hungary joins the invasion.
• 1941, 12–13 April: German forces enter Belgrade.
• 1941, 17 April: Yugoslavia signs an unconditional surrender, effective 18 April.
• 1941, July: The Partisan uprising begins.

Why it matters

The April War destroyed the first Yugoslav state in less than two weeks and opened four years of occupation, genocide and civil war that cost around a million lives. Together with the campaigns in Greece and the Battle of Crete, it gave the Axis control of the Balkans, while the bitter divisions it created shaped the region for decades, including during the breakup of Yugoslavia.