The Croatian National Guard (ZNG) was formed in May 1991 because the Yugoslav People's Army (JNA) increasingly supported the RSK and the Croatian Police were unable to cope with the situation. The ZNG was renamed the HV in November. The establishment of the military of Croatia was hampered by a UN arms embargo introduced in September. The final months of 1991 saw the fiercest fighting of the war, culminating in the Battle of the Barracks, the Siege of Dubrovnik, and the Battle of Vukovar.