With the Plitvice Lakes incident of late March/early April 1991, the Croatian War of Independence broke out between the Croatian government and the rebel ethnic Serbs of the SAO Krajina (heavily backed by the by-now Serb-controlled Yugoslav People's Army). On 1 April 1991, the SAO Krajina declared that it would secede from Croatia. Immediately after Croatia's declaration of independence, Croatian Serbs also formed the SAO Western Slavonia and the SAO of Eastern Slavonia, Baranja and Western Srijem. These three regions would combine into the Republic of Serbian Krajina (RSK) on 19 December 1991. The influence of xenophobia and ethnic hatred in the collapse of Yugoslavia became clear during the war in Croatia. Propaganda by Croatian and Serbian sides spread fear, claiming that the other side would engage in oppression against them and would exaggerate death tolls to increase support from their populations. In the beginning months of the war, the Serb-dominated Yugoslav army and navy deliberately shelled civilian areas of Split and Dubrovnik, a UNESCO world heritage site, as well as nearby Croat villages. Yugoslav media claimed that the actions were done due to what they claimed was a presence of fascist Ustaše forces and international terrorists in the city. UN investigations found that no such forces were in Dubrovnik at the time. Croatian military presence increased later on. Montenegrin Prime Minister Milo Đukanović, at the time an ally of Milošević, appealed to Montenegrin nationalism, promising that the capture of Dubrovnik would allow the expansion of Montenegro into the city which he claimed was historically part of Montenegro, and denounced the present borders of Montenegro as being "drawn by the old and poorly educated Bolshevik cartographers".