The Caucasus is a strategically important mountainous region in south-east Europe. For centuries, different powers in the region – both Christian and Muslim – have vied for control there. Modern-day Armenia and Azerbaijan became part of the Soviet Union when it formed in the 1920s. Nagorno-Karabakh was an ethnic-majority Armenian region, but the Soviets gave control over the area to Azerbaijani authorities.
It was only as the Soviet Union began to collapse in the late 1980s that Nagorno- Karabakh;s regional parliament officially voted to become part of Armenia. Azerbaijan sought to suppress the separatist movement, while Armenia backed it. This led to ethnic clashes, and – after Armenia and Azerbaijan declared independence from Moscow – a full-scale war.
Tens of thousands died and up to a million were displaced amid reports of ethnic cleansing and massacres committed by both sides. Most of those displaced in the war were Azerbaijanis. Armenian forces gained control of Nagorno-Karabakh and areas adjacent to it before a Russian-brokered ceasefire was declared in 1994. After that deal, Nagorno-Karabakh remained part of Azerbaijan, but since then has mostly been governed by a separatist, self-declared republic, run by ethnic Armenians and backed by the Armenian government.
Peace talks have taken place since then, mediated by the Organization for Security and Co-operation in Europe (OSCE) Minsk Group – a body set up in 1992 and chaired by France, Russia and the United States. But clashes continued, and a serious flare-up in 2016 saw the deaths of dozens of troops on both sides.
The conflict is further complicated by geopolitics. Nato member-state Turkey was the first nation to recognise Azerbaijan’s independence in 1991. Former Azeri President Heydar Aliyev once described the two as & ;one nation with two states;. Both share a Turkic culture and populations. Moreover, Turkey has no official relations with Armenia. In 1993 Turkey shut its border with Armenia in support of Azerbaijan during the war over Nagorno-Karabakh.