In the book “Österreich-Ungarns Aussenpolitik von der bosnischen Krise 1908 bis zum Kriegsausbruch” from 1914 , by “diplomatische Aktenstücke des österreichisch-ungarischen Ministeriums des Äussern “, part 4, authored by “Austro-Hungarian Monarchy, Ministerium des K. und K. Hauses und des Äussern”, published in 1930, we can read that Serbian soldiers, alongside the Serbian rajah (Serbian civilian population) committed many atrocities on Albanian civilians, including the sick, children, women, and murdered Turkish prisoners of war with kicks and rifle butts. They also burned down mosques. On pages 882 and 962 we can read:
“Serbs were able to report the atrocities committed against the Albanians. The order was supposedly given to murder all Albanians over the age of 8 and to exterminate the entire nation. Serbs had attacked the sick, women, and children, and on one occasion in Kumanova, killed 400 remaining Turkish soldiers with kicks and rifle butts. Entire villages were burned down, mosques destroyed, and truly unbelievable atrocities were committed. 500 Turks were killed.
According to this, the behavior of the Serbian civil and military authorities towards the foreign representatives demonstrates an ever more unbearable arrogance. The Serbian troops are indulging in cruelties against the Muslim population. Serbian Rajahs, with the active cooperation of the Serbian military, are carrying out a systematic massacre of the non-Serbian population. In Usküb (Skopje), Kumanovo and Veles, a large number people are said to have been killed.”
Reference
Balkan Academia 