Armenia and Azerbaijan have been engaged in a long-standing dispute over the Nagorno-Karabakh region, which is nominally an autonomous area within Azerbaijan. In 1923 it was allocated to the Azerbaijani SSR by a central Communist bureau, despite having a population which was almost 95 per cent ethnic Armenian at the time. In 1991, when both countries had gained independence after the dissolution of the Soviet Union, armed conflict erupted within Nagorno-Karabakh after a vote on 10 December 1991 demonstrated a vast majority in the territory in favour of independence from Azerbaijan, which subsequently rejected the proposal. In June 1992 Azerbaijan began a large scale offensive against the Nagorno-Karabakh Defence Army, which was backed by Armenia. Armenian and Azeri civilians living across borders were forced to flee to their countries of origin. Progress slowed during winter and by summer 1993 momentum favoured the Armenian forces, who managed to secure most of Nagorno-Karabakh along with territory in Azerbaijan proper.