Armenia says one of its fighter jets was shot down by a Turkey jet, in a major escalation of a conflict over the disputed Nagorno-Karabakh region.
The Armenian foreign ministry said the pilot of the Soviet-made SU-25 died after being hit by the Turkish F-16 in Armenian air space.
Turkey, which is backing Azerbaijan in the conflict, has denied the claim.
Nearly 100 people, including civilians, have died in three days of fighting over the disputed mountainous region.
The mountainous enclave is officially part of Azerbaijan, but has been run by ethnic Armenians since 1994.
Azerbaijan has repeatedly stated that its air force does not have F-16 fighter jets. However, Turkey does.
The fighting that started three days ago now appears to be spilling out of Nagorno-Karabakh.
Armenia and Azerbaijan – which have already mobilised more soldiers and declared martial law in some areas – blame each other for starting the fighting.
There are growing concerns that other countries may get directly involved in the conflict in the strategic Caucasus region.
While Turkey is backing Azerbaijan, Russia – which has a military base in Armenia – has called for an immediate ceasefire.
Nagorno-Karabakh – key facts
- A mountainous region of about 4,400 sq km (1,700 sq miles)
- Traditionally inhabited by Christian Armenians and Muslim Turks
- In Soviet times, it became an autonomous region within the republic of Azerbaijan
- Internationally recognised as part of Azerbaijan, but majority of population is ethnic Armenian
- Self-proclaimed authorities are not recognised by any UN member, including Armenia
- An estimated one million people displaced by war in 1988-94, and about 30,000 killed
- Separatist forces captured some extra territory around the enclave in Azerbaijan
- Stalemate has largely prevailed since a 1994 ceasefire
- Turkey openly supports Azerbaijan
- Russia has a military base in Armenia
What’s the background?
In 1988, towards the end of Soviet rule, Azerbaijani troops and Armenian secessionists began a bloody war which left Nagorno-Karabakh in the hands of ethnic Armenians when a truce was signed in 1994.
Tens of thousands died in fighting, and many ethnic Azerbaijanis were forced to flee their homes.
It is now a de facto independent region, relying heavily on support from Armenia. But it is not recognised by any UN member, including Armenia.
Swathes of Azeri territory around the enclave are also under Armenian control.
Negotiations have so far failed to produce a permanent peace agreement, and the dispute in the region remains one of post-Soviet Europe’s “frozen conflicts”.
Karabakh is the Russian rendering of an Azeri word meaning “black garden”, while Nagorno is a Russian word meaning “mountainous”. Ethnic Armenians prefer to call the region Artsakh, an ancient Armenian name for the area.
Over the years both sides have had soldiers killed in sporadic breaches of the ceasefire. Landlocked Armenia has suffered severe economic problems due to the closure of borders with Turkey and Azerbaijan.
Russia, France and the US co-chair the Organization for Security and Co-operation in Europe’s Minsk Group, which has been attempting to broker an end to the dispute.