Croatian Defence Council The Croatian Defence Council ( , " HVO " ) was the official military formation of the Croatian Republic of Herzeg - Bosnia , an unrecognized entity that existed in Bosnia and Herzegovina between 1991 and 1994 during the Bosnian War . The HVO was the main military force of Croats of Bosnia and Herzegovina . HVO was incorporated into the Army of the Federation of Bosnia and Herzegovina ( VFBiH ) in December 1995 by following agreement made after signing the Dayton Accords . In December 2005 HVO was reorganized as 1st Infantry ( Guard ) Regiment of the Armed Forces of Bosnia and Herzegovina , after VFBiH and Army of Republika Srpska were united into a single armed force . History . The HVO ( Croatian Defence Council ) was established on April 8 , 1992 in Grude by the political leadership of Croats , mainly members of Croatian Democratic Union ( " Hrvatska Demokratska Zajednica " ) as a military formation of Herzeg - Bosnia . Organization . HVO was located in Mostar and was divided into four corps - status operational zones : 1OZ / South - Eastern ( Herzegovina ) and 2OZ / North - Western Herzegovina , 3OZ / Central Bosnia and 4OZ / Posavina . While first three zones were grouped more or less together , Posavina was completely isolated in northern Bosnia on right bank of Sava river around Orašje and was entirely dependent on support from Croatia . There was also an HCO headqyarters in the Bihac enclave which liaised with the ABiH 5th corps . Each OZ controlled 8 - 14 infantry brigades , a military police battalion and an MP " Light Assault Battalion . " The HVO also included the brigade sized Ante Bruno Busic Regiment manned by full - time soldiers , two independent infantry battalions , a light anti - aircraft artillery battalion , Special Forces and artillery units . Guard brigades . The Guards brigades were the sections of the H . V . O which handled the army ' s heavy weapons . The H . V . O had around 50 tanks , 400 artillery pieces , and 200 armored troop carriers . Other brigades . There were 38 infantry brigades staffed by reservists , 19 had names and / or numbers and 19 only had names . The names commemorated famous or infamous figures from Croatian and Bosnian history . Each brigade had three or four battalions plus supporting elements . Two , the 107th and 109th were later transferred en masse to the ABiH due to their Moslem majorities , as did the Muslim contingent of the 108th Brigade who went on to form the ABiH ' s 108 Motorised Brigade . The 107th became the ABiH 107th " Chilvalrous " Brigade while the 109th became the 109th Mountain Brigade . 1993 Restructuring . In 1993 General Ante Roso restructured the HVO along the lines of the Croatian Army ( HV ) . The four OZ ' s were designated as Corps Districts Mosar , Tomislavgrad , Vitez and Orasje . Orasje included a much reduced Bosanska Posavina . Four Guards Brigades were formed , each manned by full - time professional soldiers . 29 brigades were reformed as three - battalion strong Home Defense Regiments ( domobranska pukovnija ) , usually with the same name and depot . Four brigades were disbanded . The military police were reduced to one Light Assault Brigade at Mostar . Eight HVO units served with the ABiH while two HVO brigades were forcibly incorporated into the ABiH . The 115th Bde became part of the ABiH 2nd Corps while the King Tvrtko Bde became part of the ABiH 1st Corps . HVO Aviation . The HVO Air Forces and Anti - aircraft Artillery was formed in 1992 and consisted of the 11th Combined Squadron , operated helicopters and transports , and the 121st Observation Squadron which operated various civilian light aircraft in an observation and communications role . There was also the 14th Anti - aircraft Missile Unit which operated several different SAM systems .