After Georgian independence, Abkhazia became the Abkhazian Autonomous Republic. The distribution of territory and the past policies of tsarist and Soviet rule meant that in 1989 the Abkhaz made up only 17.8 percent of the population of the autonomous republic named for them (compared with 44 percent Georgians and 16 percent Russians).
For two centuries, the Abkhaz had still viewed Russia as a protector of their interests against the Georgians, and tensions in Abkhazia led to open warfare on a much larger scale than in South Ossetia. In July 1992, the Abkhazian Supreme Soviet voted to return to the 1925 constitution under which Abkhazia was separate from Georgia. In August 1992, a force of the Georgian National Guard was sent to the Abkhazian capital of Sukhumi with orders to protect Georgian rail and road supply lines, and to secure the border with Russia. The Government of Georgia deployed 2,000 Georgian troops in Abkhazia. When Abkhazian authorities reacted to this transgression of their self-proclaimed sovereignty, hundreds were killed in fighting between Abkhazian and Georgian forces. Fierce fighting resulted in some 200 dead and hundreds wounded. Large numbers of refugees fled across the border into Russia or into other parts of Georgia. The Abkhaz leadership abandoned the Abkhaz capital of Sukhumi and retreated to the town of Gudauta.
A ceasefire agreement was reached on 3 September 1992 in Moscow by the Republic of Georgia, the leadership of Abkhazia and the Russian Federation. The agreement stipulated that "the territorial integrity of the Republic of Georgia shall be ensured". It also set out, as the basis of the peace settlement, a ceasefire to take effect as of 5 September 1992 and other issues including, inter alia, the disarming of illegal armed formations, the reduction of the armed forces and the exchange of prisoners. The agreement, however, was never fully implemented. The situation remained very tense with both sides accusing one another of ceasefire violations. On 1 October 1992, the ceasefire collapsed and the fighting resumed. The Abkhaz forces, supported by fighters from the North Caucasus region, quickly captured the major towns, and threatened to bring nearly 80 per cent of Abkhazia, including the capital city of Sukhumi, under their control. The raging fighting forced some 30,000 civilians to flee across the border to the Russian Federation. The parties to the conflict accused one another of human rights violations committed against the civilian population. By November 1992, the outbreak of inter-ethnic fighting in the North Caucasus region of the Russian Federation added another dimension to the already tense situation in the area.
On 24 August 1993, the Security Council, by resolution 858 (1993), decided to establish the United Nations Observer Mission in Georgia (UNOMIG), comprising up to 88 military observers, plus minimal civilian support staff, to verify compliance with the ceasefire agreement. The ceasefire, however, broke down again on 16 September 1993. Abkhaz forces, with armed support from outside Abkhazia, launched attacks on Sukhumi and Ochamchira. Notwithstanding the Security Council's call for the immediate cessation of hostilities and its condemnation of the violation of the ceasefire by the Abkhaz side, fighting continued. In the next few days, the military situation developed rapidly. On 27 September, the Abkhaz side occupied Sukhumi and a few days later all of Abkhazia. In September 1993 Abkhazian forces besieged and captured Sukhumi and drove the remaining Georgian forces out of Abkhazia. Russia was actively involved in Abkhazia's secession, helping the separatists with fuel supplies, arms shipments, and direct military support. Moscow's intervention eventually resulted in the small, poorly trained Abkhaz forces driving the Georgian army beyond the Inguri River that separates the region from the rest of the country.
Once the Abkhaz separatists won control of Abkhazia, hundreds of thousands of civilians, mostly Georgians, were displaced. Most ethnic Georgians, a large plurality of the population, were expelled or fled the region.