On June 27, 1991 (the 16th fifth month of the lunar calendar), civil war broke out in Yugoslavia.

1991 was a year when Yugoslavia developed from political turmoil to civil war and division. The fighting that broke out in June and lasted for months ruthlessly claimed tens of thousands of lives, swallowed tens of billions of dollars in wealth, and brought the federal state to the disintegration. The division of Yugoslavia and the ongoing civil war have aroused great concern and deep concern from the international community.

With the disintegration of the SADC in 1990, the formation of a multi-party system, and the victory of some opposition parties in the republic elections, the contradictions between the republics over the future state system of Yugoslavia became increasingly serious. Slovenia, Croatia and Croatia strongly demanded the implementation of a confederation and sought their own full independence. Serbia and Montenegro adhered to the federal system. In the context of intensifying ethnic tensions, the 6 0 Serb residents in Croatia have established autonomous regions since the end of 1990, declaring that they will secede from Croatia and merge into the Republic of Serbia.

The institutional dispute led to the "Head of State Crisis" in May 1991, causing the country's "collective president"-Croatian representative Mesic in the Federal Presidency to be elected as chairman of the Presidency held on the 15th of that month due to objections from Serbia and other representatives who did not obtain the required number of votes, and thus failed to be elected chairman of the Federal Presidency in accordance with the rotation order established in the Constitution. The vacancy of the chairman of the Presidency lasted for one and a half months.

On June 25, 1991, the authorities of Slovenia and Croatia simultaneously declared independence after a long period of preparation.

On the 26th, the federal government issued a statement stating that the unilateral declarations of Slovenia and Croatia that "independence is illegal and invalid." On June 27, a large-scale armed conflict broke out between the Slovenia armed forces and the People's Army of South Slav. Soon, the fighting expanded to Croatian Serb-inhabited areas and seriously escalated.

After repeated contests, the South People's Army, mainly composed of Serbs and Monsanto, basically controlled the Serb-populated areas in Croatia. On November 17, the South People's Army captured the strategic town of Vukovar in the Republic of Croatia, and more than 2,000 Croatian defenders announced their surrender.

Under the influence of the independence process of Slovenia and Croatia, the Republic of South Bosnia and Herzegovina and the Republic of Macedonia also changed their relatively moderate stance and began to seek independence. On September 8, Macedonia held a referendum on independence. On October 15, Muslim and Croatian parliamentarians, who account for 58% of the Republic of Bosnia and Herzegovina, signed the "Memorandum on the Sovereignty of Bosnia and Herzegovina." The Memorandum declares that Bosnia and Herzegovina is a sovereign country maintaining existing borders, expressing Bosnia and Herzegovina's independence tendency. On November 20, the Macedonian Parliament declared Macedonia an independent and sovereign state. So far, four of the six republics have declared independence one after another, and Yugoslavia is facing the danger of complete disintegration.

On December 26, the Presidency of the Federal Republic of Yugoslavia announced that the Serbs in Croatia, Montenegro and the Republic of Bosnia and Herzegovina would form a "Little Yugoslavia", further complicating the situation in Yugoslavia.

On December 17, the European Union held a meeting of foreign ministers. After more than 10 hours of intense debate, it was decided to recognize the independence of the two republics of Slovenia and Croatia on January 15, 1992. This decision was undoubtedly diplomatic recognition and international support for the belligerent parties in South Africa. Therefore, once the decision was announced, the civil war in South Africa further escalated, and air force and surface-to-surface missiles were even used in the conflict.