Arbitration Commission of the Peace Conference on Yugoslavia
On 20 November 1991 Lord Carrington asked: "Can the internal boundaries between Croatia and Serbia and between Bosnia and Herzegovina and Serbia be regarded as frontiers in terms of public international law?" Applying the principle of "uti possidetis juris", the commission concluded on 11 January 1992, "The boundaries between Croatia and Serbia, between Bosnia and Herzegovina and Serbia, and possibly other adjacent independent states may not be altered except by agreement freely arrived at... Except where otherwise agreed, the former boundaries become frontiers protected by international law".
Operation Winter '94
In May, the Croatian government responded by forming the Croatian National Guard ("Zbor narodne garde" – ZNG), but its development was hampered by a United Nations (UN) arms embargo introduced in September. On 8 October, Croatia declared independence from Yugoslavia, and a month later the ZNG was renamed the Croatian Army ("Hrvatska vojska" - HV). Late 1991 saw the fiercest fighting of the Croatian War of Independence, culminating in the Siege of Dubrovnik and the Battle of Vukovar. A campaign of ethnic cleansing then began in the RSK, and most non-Serbs were expelled. In January 1992, an agreement to implement the peace plan negotiated by UN special envoy Cyrus Vance was signed by Croatia, the JNA and the UN. As a result, the United Nations Protection Force (UNPROFOR) deployed to maintain the ceasefire, and the JNA was scheduled to retreat to Bosnia and Herzegovina, where further conflict was anticipated. Despite the peace arrangement requiring an immediate withdrawal of JNA personnel and equipment from Croatia, it remained on Croatian territory for seven to eight months. When its troops eventually withdrew, the JNA left its equipment to the Army of the Republic of Serb Krajina (ARSK). The January ceasefire also allowed the JNA to maintain its positions in East and West Slavonia that were on the brink of military collapse following a Croatian counteroffensive, which reclaimed 60% of the JNA-held territory in West Slavonia by the time the ceasefire went into effect. However, Serbia continued to support the RSK. The HV restored small areas around Dubrovnik to Croatian control and during Operation Maslenica it recaptured some areas of Lika and northern Dalmatia. Croatian population centres continued to be intermittently targeted by artillery, missiles and air raids throughout the war.