1988 - Nagorno-Karabakh region seeks to become part of Armenia. Ethnic Azerbaijanis begin to leave Karabakh and Armenia and ethnic Armenians leave Azerbaijan. At least 26 ethnic Armenians and six Azerbaijanis are killed in violence in Azerbaijani town of Sumqayit.
1990 - Ethnic strife between Armenians and Azeris escalates. Azeri nationalist Popular Front rallies support amid growing disorder.
Trouble flares along border between Nakhichevan exclave and Iran as rioters destroy border installations. Tension eases after Soviet and Iranian authorities agree to ease restrictions on crossing between the two countries.
Dozens die in interethnic violence in Baku. Popular Front demonstrators demand resignation of communist authorities. Soviet troops use force to end unrest, killing at least 100 people. Azeri nationalists put death toll at several hundred.
Ayaz Mutallibov becomes Azeri Communist Party leader.
Communist Party later retains power in multiparty elections but parliament has an opposition for the first time.
1991 - After failed coup attempt in Moscow, Azeri parliament votes to restore independence. In elections boycotted by opposition, Mutallibov becomes president.
Heydar Aliyev becomes leader of the Azerbaijani exclave of Nakhichevan.
Leadership of Nagorno-Karabakh declares the region an independent republic. Inter-ethnic hostilities escalate.