 As the war progressed, Armenia and Azerbaijan, both former Soviet Republics, became enveloped in a protracted, undeclared war as the latter attempted to curb a secessionist movement in Nagorno-Karabakh.The enclave's parliament had voted in favor of uniting itself with Armenia and a referendum was held with the vast majority of the Karabakh population voting in favor of independence.The demand to unify with Armenia, which proliferated in the late 1980s, began in a relatively peaceful manner; however, in the following months, as the Soviet Union's disintegration neared, it gradually grew into an increasingly violent conflict between the two ethnic groups.