Following the assassination of Archduke Franz Ferdinand in Sarajevo, anti-Serb riots broke out in various parts of the Austo-Hungarian empire. The first anti-Serb demonstrations occurred in Zagreb on the evening of 28 June, and a little later on the same evening in Sarajevo, where Serbs and Serb-owned houses and shops were attacked. Two Serbs were killed in Sarajevo on 28 June and about 1000 properties were razed or pillaged.
There were also anti-Serb riots in many other larger Austro-Hungarian cities including Dakovo, Petrinja and Slavonski Brod in modern-day Croatia, and Capljina, Livno, Bugojno, Travnik, Maglaj, Mostar, Zenica, Tuzla, Doboj, Vareš, Brcko and Šamac in modern-day Bosnia and Herzegovina.
According to some reports, the authorities stood by while the rioting occured. The Italian consul in Sarajevo claimed that the events were financed by the Austro-Hungarian government.
On the evening of 29 June, Governor Oskar Potiorek declared a state of siege in Sarajevo, and later extended it to the rest of the province of Bosnia and Herzegovina.