The Partisans initiated a guerrilla campaign that developed into the largest resistance army in occupied Western and Central Europe. The Chetniks were initially supported by the exiled royal government and the Allies, but they soon focused increasingly on combating the Partisans rather than the occupying Axis forces. By the end of the war, the Chetnik movement transformed into a collaborationist Serb nationalist militia completely dependent on Axis supplies.[15] The highly mobile Partisans, however, carried on their guerrilla warfare with great success.