The Kumanovo uprising was an uprising organized by an assembly of chiefs of the districts (Ottoman kaza) of Kumanovo, Kriva Palanka, and Kratovo in the Vilayet of Kosovo (in modern-day North Macedonia) in 1878. The movement sought to liberate the region from the hands of the Ottoman Empire. Following the Serbian Army's liberation of Niš on 12 January 1877, the rebellion began on 20 January 1878 with guerrilla operations during the army's liberation of Vranje. The rebels received secret aid from the Serbian government. The uprising lasted four months until its suppression by the Ottomans on 20 May, during which the Ottomans retaliated with atrocities on the local population. Background Serbian-Ottoman War The Herzegovina Uprising (1875–77), backed unofficially by the states of Serbia and Montenegro, sparked a series of rebellions against the Ottoman Empire throughout Europe, such as the Bulgarian April Uprising and that of Velika Begovica. Serbia and Montenegro jointly declared war on the Ottoman Empire on 18 June 1876. Throughout the following two months, the ill-prepared and poorly equipped Serbian Army, though aided by Russian volunteers, failed to achieve offensive objectives. However, the army did manage to repulse the Ottoman offensive into Serbia, and on 26 August, Serbia pleaded European powers to mediate in ending the war. An ultimatum given by European powers forced the Ottoman Porte to give Serbia a one-month ceasefire and start peace negotiations. The Turkish peace conditions, however, were refused by European powers as too harsh. In early October, after the truce had expired, the Ottoman Army resumed its offensive and the Serbs quickly became desperate. As a result, on 31 October 1876, Russia issued an ultimatum requiring the Ottoman Empire to stop hostilities and sign a new truce with Serbia within 48 hours, a demand backed by the mobilization of up to 20 divisions of the Russian Army. Sultan Abdul Hamid II accepted the conditions of the ultimatum, however, the Ottoman brutality in the war and the violent suppression of the Herzegovina Uprising provoked political pressure within Russia, which saw itself as the protector of the Serbs, to act against the Ottoman Empire. This led to the Russo-Turkish War (24 April 1877 – 3 March 1878). The Serbian Army advanced into Old Serbia and liberated Niš on 12 January 1878 and then Vranje on 31 January 1878. The wars of Serbia and Montenegro, and then Russia, against the Ottomans motivated liberation movements among