The Zrinski Battalion trained volunteer troops in Vukovar in June 1991 before it saw action in Hrvatska Kostajnica , the Battle of Gospić and near Slano in 1991 . By the end of 1991 , the unit 's personnel were tasked with setting up an additional special forces unit of the HV . The next year its elements took part in the Battle of Kupres and Operation Tiger aimed at lifting the Siege of Dubrovnik . It also and helped develop and train the Croatian Defence Council ( Hrvatsko vijeće obrane – HVO ) , setting up a training camp in Tomislavgrad . In 1993 , the battalion took part in Operation Maslenica . In February 1994 , the Zrinski Battalion was amalgamated with several other HV special forces units into the 1st Croatian Guards Brigade ( 1 @.@  hrvatski gardijski zdrug ) , a component of the 1st Croatian Guards Corps ( 1 @.@  hrvatski gardijski zbor ) .