evidence: What’s Nagorno-Karabakh and Why Do Azerbaijan and Armenia Fight Over It? Since the collapse of the Soviet Union, the republics of Azerbaijan and Armenia have clashed repeatedly over the territory of Nagorno-Karabakh. During a short war in 2020, Azerbaijani forces backed by Turkey regained control of seven surrounding districts that had been occupied by Armenians since the early 1990s. Azerbaijan also took over part of Nagorno-Karabakh itself, a territory largely populated by Armenians but which is internationally recognized as part of Azerbaijan. While a truce brokered by Russian President Vladimir Putin halted fighting then, energy-rich Azerbaijan and landlocked Armenia haven’t reached a final peace agreement. On Sept. 19, Azerbaijan started a military operation again to take full control of the region, halting it the next day under an agreement mediated by Russian peacekeepers. By the end of the month, more than half of Nagorno-Karabakh’s population had fled to Armenia amid accusations of ethnic cleansing. Local leaders said they’d disband and hand over to Azerbaijan by Jan. 1.