Genocide of Serbs in the Independent State of Croatia

• 1. Introduction

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  The Genocide of Serbs in the Independent State of Croatia began in April 1941, when a fascist puppet regime called the NDH came to power and set about eliminating Serbs from its territory with a stated formula: one-third to be killed, one-third expelled, one-third forcibly converted to Catholicism. Between 1941 and 1945, the Ustaše regime murdered somewhere between 200,000 and 500,000 Serbs. It built concentration camps, dispatched death squads into villages, and erected the only Axis satellite state to establish camps specifically for children. Who were the Ustaše, and how did a movement rooted in 19th-century nationalist theory become the instrument of one of the most lethal campaigns of mass killing in wartime Europe? What role did the Catholic Church play? Why did the postwar world barely notice? And how do Serbs and Croats reckon with this history today?

• 2. Roots of Hatred

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  Ante Starčević founded the Party of Rights in the 19th century and became what Milovan Đilas called the "father of racism" and "ideological father" of the Ustaše. Starčević called Serbs an "unclean race", a "nomadic people" and "a race of slaves, the most loathsome beasts". His co-founder Eugen Kvaternik denied that Serbs in Croatia even existed as a distinct people, seeing their political awareness as a threat to Croatian ambition.

  When Josip Frank broke from Starčević's party and formed the Pure Party of Rights, he kept that hostility and amplified it. His followers, called the Frankists, made anti-Serb attitudes a defining characteristic of their movement. Historian John Paul Newman traced a direct line from those Frankists into the Ustaše, noting that their experience of World War I deepened the grievance. Croatia had fought on the losing Austro-Hungarian side; Croat officers had actually served as military governors of occupied Serbia and supported Austria-Hungary's plans to absorb a weakened Serbian state.

  Early 20th-century intellectuals added pseudo-scientific weight to this hatred. Ivo Pilar, a historian, politician and lawyer, argued that Croats carried a "Nordic-Aryan" heritage while Serbs had "interbred" with the "Balkan-Romanic Vlachs". Archaeologist and historian Ćiro Truhelka claimed Serbs belonged to a "degenerate race". These theories fed directly into what Ustaše officials would later call racial policy.

  In 1928, the murder of Stjepan Radić, the leader of the Croatian Peasant Party, in the parliamentary chamber by a Montenegrin Serb deputy named Puniša Račić shook Croatian politics and handed the radical right a grievance that was both real and exploitable. When King Alexander then proclaimed a royal dictatorship in an attempt to forge "integral Yugoslavism", the separatist forces surged. The most extreme among them was a movement founded by journalist Gustav Perčec and a lawyer named Ante Pavelić in late 1929 or early 1930.

• 3. The Ustaše Movement

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  Ante Pavelić had been working toward violent separatism since at least 1927, when he secretly contacted Benito Mussolini and presented his vision of an independent Greater Croatia covering the entire historical and ethnic territory of the Croats. Mussolini was interested: he wanted to isolate Yugoslavia and extend Italian influence along the Adriatic. British historian Rory Yeomans notes evidence that Pavelić had been considering a nationalist insurgency as early as 1928.

  Mussolini provided the Ustaše with financial and ideological support, and the movement established its first center in Vienna, where anti-Yugoslav propaganda was developed and agents were trained for terrorist operations. In 1932, the Ustaše launched the so-called Velebit uprising, assaulting a police station in the village of Brušani in Lika. In 1934, in cooperation with Bulgarian, Hungarian and Italian right-wing extremists, they assassinated King Alexander I while he visited the French city of Marseille.

  In 1933, the movement issued "The Seventeen Principles", its official ideology. The document declared the uniqueness of the Croatian nation, promoted collective rights over individual rights, and stated that people who were not Croat by "blood" would be excluded from political life. Genocide was being planned explicitly years before any war. One of Pavelić's main ideologues, Mijo Babić, wrote in 1932 that the Ustaše "will cleanse and cut whatever is rotten from the healthy body of the Croatian people".

  Following the Axis invasion of Yugoslavia in April 1941, Pavelić's closest associate Slavko Kvaternik announced the formation of the Independent State of Croatia on a Radio Zagreb broadcast after Nazi forces entered the capital on the 10th of April. Pavelić arrived from Italy, declared a new government on the 16th of April, and gave himself the title "Poglavnik" , the Croatian equivalent of Führer. Serbs made up approximately 30% of the NDH population, and by the Ustaše's own stated formula, all of them had to go.

• 4. Jasenovac and the Camps

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  There were between 22 and 26 concentration camps in the NDH in total. The Jasenovac-Stara Gradiška complex was the largest extermination camp in the Balkans, and an estimated 100,000 inmates perished there, the majority of them Serbs. Vjekoslav "Maks" Luburić, the commander-in-chief of all Croatian camps, announced the camp's "efficiency" at a ceremony on the 9th of October 1942 and boasted that Jasenovac had killed more people than the Ottoman Empire managed during its occupation of Europe.

  The Ciglana camp, a former brickyard converted into the main killing ground, recorded a mortality rate of 88%, compared to Auschwitz's 84.6%. A furnace was engineered into a crematorium. Survivor testimony described children being burnt alive and the stench of human flesh spreading through the camp. Luburić had a gas chamber built at Stara Gradiška, where a considerable number of inmates were killed in a three-month experiment using sulfur dioxide and Zyklon B, but the method was abandoned due to poor construction. Most inmates died instead from starvation, disease, and one-on-one brutality: guards attacked barracks with mallets, maces, axes and knives. The camp developed a custom tool, the srbosjek, a glove with an attached curved blade designed specifically for cutting throats.

  Camp commandant Miroslav Filipović, dubbed "fra Sotona" ("brother Satan"), once drowned Serb women and children by flooding a cellar. Guard Petar Brzica, a former Franciscan priest, was reported to have won a throat-cutting contest on the 29th of August 1942 after killing 1,360 inmates. When Partisan and Allied forces closed in at the end of the war, the Ustaše began mass liquidations, shot most remaining male inmates, then torched buildings and documents before fleeing.

  Approximately 90,000 of all Serb genocide victims perished inside concentration camps. The historian Jozo Tomasevich described the Jadovno camp as a "way station" leading to pits on Mount Velebit, where inmates were executed and dumped. The NDH was also the only Axis satellite to build camps specifically for children. Diana Budisavljević, a humanitarian of Austrian descent, managed to save more than 15,000 children from Ustaše camps. The Sisak children's camp alone saw 6,693 children pass through it.

• 5. Village Massacres

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  The first act of mass murder after the Ustaše came to power took place on the 28th of April 1941, when approximately 184-196 Serbs from Bjelovar were summarily executed following arrest orders by Kvaternik. A few days later, 331 Serbs in the village of Otočac were rounded up and forced to dig their own graves before being hacked to death with axes. The local Orthodox priest was made to recite prayers for the dying as his son was killed beside him; he was then tortured, his eyes gouged out, before being skinned alive.

  By July 1941, the violence had become, in the words recorded at the time, "indiscriminate, widespread and systematic". Firearms were rarely used in the village massacres; knives, axes and similar weapons were more common. A Gestapo report to Reichsführer SS Heinrich Himmler dated the 17th of February 1942 stated that Ustaše units had committed atrocities "in a bestial manner not only against males of conscript age, but especially against helpless old people, women and children", estimating that approximately 300,000 Orthodox people had been killed or tortured to death.

  On the 24th of July 1941, the entire Serb population of Banski Grabovac, some 1,100 peasants, was murdered. In Bosnian Krajina, on the Eastern Orthodox Elijah's holy day in August 1941, between 2,800 and 5,500 Serbs from Sanski Most and the surrounding area were killed and thrown into pits dug by the victims themselves. In February 1942, under the command of Miroslav Filipović, the Ustaše massacred 2,300 adults and 550 children in the Serb-populated villages of Drakulić, Motike and Šargovac. Children were chosen as the first victims.

  Historian Jonathan Steinberg stated that the crimes against Serbs in the NDH were the "earliest total genocide to be attempted during the World War II". Historian Michael Phayer noted that some estimates place the beginning of the Nazi decision to kill all of Europe's Jews in the latter half of 1941, which, if correct, would mean the Croatian genocide began before the systematic Nazi killing of Jews. American historian Stanley G. Payne described the killings as an "extraordinary mass crime" that in proportionate terms exceeded every European regime except Hitler's Third Reich, surpassed elsewhere only by the Khmer Rouge in Cambodia and several extremely genocidal African regimes.

• 6. Religious Persecution

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  On the 3rd of May 1941, the NDH passed a law on religious conversions pressuring Serbs to adopt Catholicism and thereby become legally Croatian. The law was passed on the eve of Pavelić's meeting with Pope Pius XII in Rome. The Catholic Church in Croatia, headed by Archbishop Aloysius Stepinac, greeted it and incorporated it into the Church's internal law. The term "Serbian Orthodox" was banned in mid-May as incompatible with state order and replaced officially with "Greek-Eastern faith".

  Of the 577 Serbian Orthodox priests, monks and other religious dignitaries present in the NDH in April 1941, there were none left by December. Between 214 and 217 were killed, 334 were exiled, eighteen fled and five died of natural causes. Over 150 Serbian Orthodox priests were killed between May and December 1941 alone. Churches dating to the 1200s and 1300s were razed or turned into stables and barns. In Lika, Kordun and Banija alone, 172 Serbian Orthodox churches were closed, destroyed, or looted.

  The conversion policy had a deliberately selective character: only uneducated Serbs were eligible, since illiterate peasants were presumed to have less fixed Orthodox identity. Educated Serbs, Orthodox clergy in particular, were not eligible for conversion. They were targeted for expulsion or death instead. In 1941-1942, some 200,000 to 250,000 Serbs were converted to Roman Catholicism, although most practiced it only temporarily and de-converted after the war. Converts were sometimes killed anyway, often in the same churches where they were re-baptized.

  On the 6th of February 1942, Pope Pius XII privately received 206 uniformed Ustaše members and blessed them. On the 8th of February 1942, the NDH envoy to the Holy See, Nikola Rušinović, reported that "the Holy See rejoiced" at the forced conversions. The Encyclopedia of the Holocaust noted that the bishops' conference that met in Zagreb in November 1941 was not prepared to denounce the forced conversions or the murder of Serbs and Jews. The NDH government later established a puppet Croatian Eastern Orthodox Church on the 3rd of April 1942, hoping to Croatianize the remaining Serb population once it became clear that total eradication was unattainable.

• 7. The World's Silence

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  The United States ambassador to the Kingdom of Yugoslavia, Arthur Bliss Lane, sent a telegram reporting persecution of Jews and Serbs in Zagreb immediately following the Axis invasion. In June 1941, a Standard Oil employee who had recently left Zagreb provided evidence of persecutions to the United States delegation in Geneva. By August 1941, a former US diplomat received a letter with photographs describing "a comprehensive policy aiming at the extermination of the Serbian race". That letter was submitted to the State Department and to Yugoslav government-in-exile ambassador Constantin Fotich, who provided a memorandum to Franklin D. Roosevelt on the 20th of December 1941.

  By early 1942, Secretary of State Cordell Hull was receiving daily reports from the US consul-general in Istanbul detailing the killings. Yet despite Roosevelt personally assuring the exiled King Peter II of Yugoslavia that the Ustaše would have to pay for their crimes after the war, the White House issued no public statements and took no action. The State Department made only one formal inquiry: on the 29th of September 1941, Hull asked the American embassy in Rome to investigate reports of mass deportations of Serbs from Croatia. No response was ever received.

  German officials themselves were alarmed. In September 1942, General Alexander Löhr met with Hitler to urge Pavelić to stop the attacks on Serbs, arguing that the anti-Serb policies had driven most of the NDH's Serb population to support the Partisans. Hitler laughingly dismissed Löhr's concern, saying the Ustaše was simply "letting off a little steam".

  After the war, the Yugoslav communist government compounded the silence. Tito's regime feared that fully accounting for the genocide would inflame Serb-Croat tensions and destabilize the new communist state. Tito passed through Jasenovac several times and never once visited the site. Historians Marko Attila Hoare and Mark Biondich later observed that Western historians do not pay enough attention to the genocide committed by the Ustaše, and several scholars have described it as a lesser-known genocide. The suppression of the topic left a vacuum that Serbian and Croatian nationalist movements would both exploit during the breakup of Yugoslavia in the 1990s.

• 8. Reckoning and Classification

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  Raphael Lemkin, the jurist who coined the word genocide and initiated the Genocide Convention, described the Ustaše mass killings of Serbs as meeting the definition of genocide. Yad Vashem, Israel's official Holocaust memorial, has stated that the Ustasha carried out a Serb genocide. The Simon Wiesenthal Center similarly identified the leaders of the Independent State of Croatia as having committed genocide against Serbs, Jews and Roma.

  In the 1980s, Serb statistician Bogoljub Kočović and Croat demographer Vladimir Žerjavić independently calculated wartime casualties in Yugoslavia. Historian Jozo Tomasevich described their studies as objective and reliable. Kočović estimated that 370,000 Serbs, combatants and civilians combined, died in the NDH, with the figure possibly as high as 410,000. Žerjavić put the total Serb death toll in the NDH at 322,000, of which 197,000 were civilians. Historian Rory Yeomans stated that the most conservative estimates place Serb deaths at 200,000, with the actual number possibly reaching 500,000.

  Postwar trials did bring some perpetrators to account. NDH official Mile Budak and others were tried and convicted of war crimes by Yugoslav communist authorities. Camp commandant Miroslav Filipović was found guilty, sentenced to death and hanged. Jasenovac commandant Ljubo Miloš was captured through Operation Gvardijan and executed. Archbishop Aloysius Stepinac was convicted of high treason and forced conversion. Ante Pavelić himself escaped to Latin America, as did many others.

  In 2018, Croatian historian Mirjana Kasapović wrote that in the most important scientific works on genocide, the crimes against Serbs, Jews and Roma in the NDH are unequivocally classified as genocide. In 2025, a Croatian fact-checking outlet published an analysis noting the classification remains debated among some historians due to differing interpretations of genocidal intent and whether the evidence demonstrates a centrally planned policy of total extermination. Serbia marks the 22nd of April as a public holiday dedicated to victims of genocide and fascism, while Croatia holds an official commemoration at the Jasenovac Memorial Site each year.