Following the Axis invasion of Yugoslavia in April 1941, Drljević began cooperating with the Italian authorities occupying Montenegro. In July, he proclaimed the reestablishment of the Kingdom of Montenegro, but his attempt to establish an Axis-aligned puppet state triggered an immediate uprising. That September, Italian authorities sent him to an internment camp in Italy after the outbreak of an anti-fascist revolt. Drljević escaped the camp several months later and made his way into the German-held half of the Independent State of Croatia (NDH). In the summer of 1944, he created the Montenegrin State Council in Zagreb.