 Ljotić remained on active service after the war ended, with a unit guarding the border between the newly formed Kingdom of Serbs, Croats and Slovenes and the Kingdom of Italy near the town of Bakar.During this time, he also worked for the intelligence service of the Kingdom of Serbs, Croats and Slovenes.In 1919, he helped break a railway strike meant to disrupt the flow of munitions intended for anti-Communist forces fighting against Béla Kun in Hungary.