On April 6, 1941, German aircraft appeared over Belgrade before dawn. Within hours, bombs were falling on the Yugoslav capital.
Entire districts were destroyed. Thousands of civilians were killed or wounded, and the Yugoslav army collapsed in less than two weeks.
The country disintegrated, divided between occupying powers and puppet regimes. A large part of Serbia was placed under direct German military administration.
From the outset, rule was enforced through fear. Arrests, executions of hostages, and reprisals against civilians became routine instruments of control.
Villages suspected of sheltering resistance fighters were burned. Communities were punished collectively for acts they had not committed.
Resistance movements emerged soon after the occupation. Among them were the nationalist Chetniks led by General Draža Mihailović, and the communist partisans under Josip Broz Tito.
In the first years of occupation, the Germans regarded Mihailović's forces as a serious threat, especially in mountainous regions where guerrilla warfare flourished.
In central Serbia, Major Dragutin Keserović commanded the Rasina Corps, a Chetnik formation. His units operated in the Kopaonik mountain area and maintained strong ties with the local population.
During 1942, Allied aircraft reportedly dropped weapons and equipment to Chetnik detachments in this region. German suspicion grew that it had become a center of organized resistance.
The decision to launch Operation Kopaonik, a large Axis offensive against the Chetnik movement in central Serbia, was shaped at the highest levels of the SS. Heinrich Himmler believed the annihilation of Mihailović and his commanders was essential for securing Serbia and stabilizing southeastern Europe.
The plan was prepared on September 30, 1942. The formal order for its execution was issued one week later, on October 5.
The main striking force was the 7th SS Volunteer Mountain Division Prinz Eugen. Created at the end of 1941, it was recruited largely from the ethnic German minorities of southeastern Europe, known as Volksdeutsche.
The division was named after Prince Eugene of Savoy, a historical commander celebrated for his wars in the Balkans in the 17th and 18th centuries. It was not designed for conventional front-line warfare, but for anti-partisan operations.
From the beginning, it was shaped as an instrument of terror. Its first commander, Artur Phleps, trained the unit for mountain warfare and harsh reprisals against civilians.
Villages suspected of supporting resistance were to be destroyed. Civilians were treated as potential enemies.
Alongside the SS division, several battalions of the Bulgarian 9th Infantry Division and elements of the Russian Protective Corps took part in the operation. The overall commander of Axis forces was SS-Brigadeführer Artur Phleps.
One of the main regiments involved was the 14th SS Infantry Regiment, commanded by August Schmidthuber. Its battalions were led by officers including Richard Kaas and others.
In total, more than 7,000 Axis soldiers were mobilized for the offensive against the Chetniks in the Serbian mountains. Phleps instructed his troops to regard the entire population of the region as sympathizers of the rebels.
That order removed any distinction between armed fighters and civilians. Operation Kopaonik was officially presented as a military action against insurgents, but from the outset it carried the character of a punitive expedition.
The offensive began on October 11, 1942. German battalions advanced toward the Kopaonik region from Kosovska Mitrovica, Raška, and Novi Pazar, while Bulgarian forces moved from Brus and Aleksandrovac.
On October 12, Axis troops completed the encirclement of a small rural village, Kriva Reka. It was believed to be the headquarters of Keserović's Rasina Corps, and possibly the location of a British military mission.
But Keserović and his soldiers had been warned. He withdrew his forces into the mountains before the Axis encirclement closed.
The main military objective failed, and the Chetnik units escaped. For the German command, however, failure was not an option. Harsh reprisals would follow.
After troops entered Kriva Reka, they began a campaign of systematic destruction. Around 330 civilians were massacred.
Of these, 270 were local inhabitants, nearly half of the village's population, while more than 60 came from nearby settlements.
At least 46 victims were forced into the local church. The doors were locked, and the building was blown apart by explosives.
Men, women, children, and elderly people who survived the initial explosion were burned alive. Those who tried to escape were shot.
The massacre left Kriva Reka in ruins. One hundred houses were destroyed, and thousands of livestock were stolen.
The violence did not end there. Nearby villages were looted and destroyed, and hundreds more civilians were killed across the region.
In total, Axis forces killed approximately 690 civilians during the operation in Kriva Reka and the neighboring area.
Even within the German military administration, the scale of brutality caused unease. Paul Bader, the German military commander in Serbia, later requested that the Prinz Eugen Division refrain from killing civilians and burning villages without specific justification.
His concern was linked to discipline and long-term stability, not humanitarian principles. Nevertheless, the order acknowledged that the violence in Kriva Reka had been extreme even for the Germans.
Despite the failure to eliminate Keserović and his units, Heinrich Himmler expressed satisfaction with the performance of the Prinz Eugen Division. Shortly after the operation ended, he visited the division for three days.
On October 18, 1942, he arrived in Kraljevo, a city in central Serbia, and celebrated the birthday of Prince Eugene of Savoy together with members of the division. Official praise overshadowed the civilian deaths.
Operation Kopaonik marked only the beginning of a broader campaign of terror by the Prinz Eugen Division. Through the winter of 1942 and into 1943, the division conducted further anti-partisan operations across Serbia, Bosnia, and Montenegro.
Villages were burned, civilians executed, and entire communities destroyed. In early 1943, the division participated in large offensives against partisan forces, including operations that resulted in thousands of civilian deaths.
Military objectives were often not achieved, but civilian populations paid the price. The pattern was consistent: encirclement, search, looting, burning, and execution.
The massacre at Kriva Reka thus became part of a wider history of violence in occupied Yugoslavia. But the men from the SS Division Prinz Eugen did pay for their crimes.
Among them was Artur Phleps, who had been promoted to SS-Obergruppenführer and commanded the division during the massacre. By the autumn of 1944, German control in southeastern Europe was disintegrating.
Romania had changed sides in August. Soviet forces were advancing rapidly, and German units were retreating in confusion.
On September 21, 1944, Phleps was traveling with only his adjutant and driver near the city of Arad in western Romania. He was attempting to assess the situation at the front while on his way to meet Heinrich Himmler in Berlin.
Unaware that Red Army units had already reached the area, he entered the village of Șimand. Soviet troops were already present, and Phleps was captured without resistance.
He was taken for interrogation and held in a local building. Later that same day, German aircraft attacked the village.
During the chaos of the bombing, Phleps and other prisoners attempted to escape. Soviet guards opened fire, and Phleps was shot and killed.
August Schmidthuber, commander of the 14th SS Infantry Regiment during the massacre at Kriva Reka and later commander of the division, survived the fighting but not the aftermath of the war.
After Germany's defeat, the remnants of the division surrendered on May 11, 1945, near the city of Celje in Slovenia, to Yugoslav partisan forces.
Schmidthuber was taken into custody and transferred to Yugoslav authorities. He was brought before a military tribunal.
He was charged with direct participation and command responsibility for massacres, deportations, and systematic violence against civilians across Serbia, Bosnia, Montenegro, and Croatia.
The court found him guilty. On February 19, 1947, Schmidthuber was executed by hanging in Belgrade.
Bernhard Kasche, commander of one of the battalions involved in Operation Kopaonik, did not fare any better. After the war, he was captured in Norway and extradited to Yugoslavia.
He was tried for war crimes, including those committed in Kriva Reka. He was sentenced to death and hanged in Belgrade on January 24, 1947.
For the ordinary soldiers of Prinz Eugen, the end was far more chaotic and brutal. When the division surrendered after the war in Europe ended on May 8, 1945, thousands of its members fell into Yugoslav captivity.
Almost all personnel of the division taken prisoner by the Yugoslav army were subsequently killed. These killings were carried out by partisan units at a local level, often as acts of revenge for years of terror and destruction.
One of the largest known executions took place near the town of Brežice, in the eastern part of present-day Slovenia. Around May 22, 1945, approximately 2,000 former members of the division, many of them ethnic Germans, were stripped naked, bound together with wire, shot, and buried in a mass grave in an abandoned trench.
Later discoveries of mass graves in the area confirmed the scale of these killings. Similar executions occurred elsewhere, though exact numbers remain uncertain to this day.