The Chetniks were a Serbian nationalist group formed in 1904. The Chetniks were formed to protect the Serbian minorities in Macedonia during the late nineteenth century, and the name was later adopted by nationalist guerrillas fighting initially with British support against the German and Italian occupying forces during World War II. Led by Draza Mihailovic, they were initially supported by the Allied Powers against Nazi Germany's occupying forces, but they were involved in ethnic cleansing and later collaborated with the Axis Powers against Josip Broz Tito's Yugoslav Partisans. They massacred Croats in mixed Serbian-Croat areas and Bosnian Muslims in Bosnia, Herzegovina, and Montenegro, and, after the war, Mihailovic and most of the leaders of the Chetniks were either executed or imprisoned for war crimes and treason. Once Croatia moved towards independence from around 1990, new Serbian guerrilla units formed under the name, fighting against Croatian control of areas with a substantial Serb population.