Cited from the publication “Roots of the Insurgency of Kosovo”, page 3:

“About 76,000 Serbian forces entered Kosovo and defeated a disorganized force of 16,000 Turks. As they advanced through Kosovo, Serbians destroyed Albanian villages. Serbia viewed the subjugation of Kosovo in October 1912 as the fulfillment of a historic crusade. Serbian atrocities against Albanians, especially those committed by paramilitary bands called “chetniks,” suggested to some contemporary Western observers that Serbia was bent on a systematic extermination of Kosovo’s Muslim population to transform the ethnic character of Kosovo”.

Source

https://www.ausa.org/sites/default/files/BB-82-Roots-of-the-Insurgency-in-Kosovo.pdf