Z - 4 plan The Z - 4 Plan or Draft agreement on the Krajina , Slavonia , Southern Baranja and Western Sirmium stands for the Zagreb 4 peace proposal to end the Croatian War of Independence . The proposal was made by the Zagreb 4 group ( also known as the Mini - Contact Group ) and would have reintegrated the Republic of Serbian Krajina into Croatia . The Zagreb 4 group consisted of the United States ( through former Secretary of State Cyrus Vance ) , Russia , and the European Union ( though France and Germany ) . Their plan was never implemented due to the onset of Operation Storm , a military operation in which Croatia defeated the Krajina Serbs and captured its territory . Outline of the plan . The plan was meant to allow for the reintegration of the Republic of Serbian Krajina into Croatia by offering wide - ranging autonomy through most of Serbian Krajina . In addition , the plan called for the return of all Croatian refugees . However , the plan would have required UNPROFOR to extend its mandate in order to implement the agreement , and the Croatian constitution would have to have been amended to accommodate the requirements of autonomy . Some aspects of the proposed autonomy included the following : Croatian reactions . The plan was given to Croatian and Krajina authorities by the EU in January , 1995 . Croatia accepted the plan as a basis for future negotiations , but found many parts of it unacceptable . Some in the Croatian opposition supported the Z - 4 Plan . However , MPs from the right - wing parties called for the automatic rejections of the agreement . Croatia is organized as a unitary state , and many viewed acceptance of the plan as a step to the federalization and confederalization of the state , both of which were unacceptable . The plan was also opposed because it would have required amending the constitution in significant ways . Croatia had also stated that it would not extend UNPROFOR ’ s mandate in Croatia past March 31 . Croatia did accept the parts of the plan that concerned the establishment of Croatian sovereignty on its entire territory , return of the refugees , and local self - administration for the Serbian ethnic communities . However , Croatia rejected the aspects that exceeded the limits of constitutional provisions and international conventions on the rights of ethnic communities or minorities . Reactions from Belgrade ( Serbia ) . The Krajina authorities refused to even consider the plan because it required reintegration with Croatia . Their official response , however , was that there would be a freeze on talks with Croatia until Croatia changed its attitude towards Krajina . The authorities in Belgrade accepted the plan but only on the conditions that sanctions against Yugoslavia were to be lifted ; however , despite this , Krajina authorities still refused to accept the plan . In Yugoslavia , only the Serbian Renewal Movement called for outright acceptance of the plan . Slobodan Milošević eventually stated that he agreed with the plan , but that it was up to the Krajina Serbs to accept or reject it . One reason Milošević said this was because Yugoslavia was planning at the time to diplomatically recognize Croatia , but this was unlikely to occur unless an agreement was reached between the Serbs in Krajina and the Croatian government . Milošević had some concerns about the plan because he believed that if Croatia accepted the plan in its initially unacceptable form , Yugoslavia may have been forced to accord the same status to Vojvodina , Kosovo and Sandžak . In Belgrade , Vojislav Šešelj ( founder of the nationalist far - right Serbian Radical Party ) said that the self - proclaimed Serbian states in Croatia and Bosnia ( the Republika Srpska ) should declare a union between their two states . Other people called for Yugoslavia to recognize Krajina as being a state , just as Turkey did to the Turkish Republic of Northern Cyprus , and Albania had done with the Republic of Kosova from 1990 - 1999 . Ultimate rejection . On August 2 , negotiations took place in Geneva for Krajina to enter a political settlement with Zagreb . The basis for negotiations in Geneva was a modified version of the Z - 4 Plan which would treat the eastern and western part of Krajina equally . On August 2 , Krajina Prime Minister Milan Babic publicly declared his acceptance the Z - 4 Plan through negotiations with U . S . Ambassador to Croatia Peter Galbraith . Croatia refused to acknowledge the plan ' s acceptance by Krajina authorities , since Krajina president Mile Martić refused even to receive plan .