Here is a look at the history of the conflict and the latest developments.
WHAT IS NAGORNO-KARABAKH?
Nagorno-Karabakh, known as Artsakh by Armenians, is a landlocked mountainous area in the Caucasus region. It is internationally recognised as part of Azerbaijan but its inhabitants are predominantly ethnic Armenians, who number about 120,000. They have their own government which has enjoyed close links to Armenia's but has not been officially recognised by Armenia or any other country.
Armenians, who are Christians, claim a long presence in the area, dating back to several centuries before Christ. Azerbaijan, whose inhabitants are mostly Muslim, also claims deep historical ties to the region, which over the centuries has come under the sway of Persians, Turks and Russians. Under the Soviet Union, Nagorno-Karabakh became an autonomous region within the Soviet republic of Azerbaijan.
FIRST KARABAKH WAR
As the Soviet Union crumbled, what is known as the First Karabakh War (1988-1994) erupted between Armenians and their Azerbaijani neighbours. About 30,000 people were killed and more than a million people displaced, most of them Azeris driven from homes when the Armenian side ended up in control of Nagorno-Karabakh itself and swathes of seven surrounding districts of Azerbaijan.
44-DAY WAR IN 2020
In 2020, after decades of intermittent skirmishes, Azerbaijan began a military operation which became the Second Karabakh War, swiftly breaking through Armenian defences. It won a resounding victory in the 44-day war, taking back the seven districts and about a third of Karabakh itself.
The use of drones bought from Turkey and Israel was cited by military analysts as one of the main reasons for Azerbaijan's victory. At least 6,500 people were killed.
Russia, a treaty ally of Armenia but which also has good relations with Azerbaijan, stepped in to negotiate a ceasefire.
The deal provided for 1,960 Russian peacekeepers to deploy to Karabakh to guard the only road left linking the enclave with Armenia - the so-called Lachin corridor.
PEACE TALKS
Analysts say successive rounds of talks, mediated variously by the European Union, the United States and Russia, have brought the two sides closer to a permanent peace treaty than they have been for years, but a final settlement remains elusive. The most sensitive issue is the status of the 120,000 ethnic Armenians in Karabakh, whose rights and security Armenia says must be guaranteed. Armenian Prime Minister Nikol Pashinyan has said his country recognises the sovereignty and territorial integrity of Azerbaijan, but Baku says it does not trust that assertion was made in good faith and accuses Armenia of "fuelling separatism".
HUMANITARIAN CRISIS
In December 2022 Azeri civilians identifying themselves as environmental activists began blocking the Lachin corridor, and in April 2023 Azerbaijan established a new security checkpoint along it. These moves have cut off the flow of people and goods between Armenia and Nagorno-Karabakh except for urgent medical evacuations, creating what the United States and others have called a "rapidly deteriorating humanitarian situation". Azerbaijan says it acted to prevent the road being used to smuggle weapons.
In a possible breakthrough, ethnic Armenian authorities in Karabakh said on Saturday they had agreed to let in aid shipments from Baku-held territory for the first time in decades, in return for the reopening of the Lachin corridor. But uncertainty surrounds the implementation of the agreement.
Meanwhile Armenia and Azerbaijan have accused each other of building up troops near their shared border and around Karabakh in the past week, prompting fears among residents of both capitals that war could break out again. Russia has been heavily distracted by its war in Ukraine, raising doubts about its ability to maintain peace despite its assertion that it remains the security guarantor in the region.
(Reporting by Reuters)
