Clashes erupted between Armenia and Azerbaijan over the volatile Nagorno-Karabakh region, reigniting concern about instability in the South Caucasus, a corridor for pipelines transporting oil and gas to world markets.
Both sides, which fought a war in the 1990s, reported fatalities. Armenia and Nagorno-Karabakh, a breakaway region that is inside Azerbaijan but is run by ethnic Armenians, declared martial law and mobilised their male populations.
Armenia said Azerbaijan had carried out an air and artillery attack on Nagorno-Karabakh. Azerbaijan said it had responded to Armenian shelling and that it had seized control of up to seven villages, but Nagorno-Karabakh denied this.
The clashes prompted a flurry of diplomacy to prevent a new flare-up of a decades-old conflict between majority Christian Armenia and mainly Muslim Azerbaijan, with Russia calling for an immediate ceasefire and Pope Francis leading calls for talks.
Turkish President Tayip Erdogan, with close ties to Azerbaijan and major investments in the country, called on Armenia to cease its aggression.
Armenia and Turkey have no diplomatic relations, with many countries, including Cyprus, recognising a genocide against Armenians by the Ottoman Turks in 1915.
Pipelines shipping Caspian oil and natural gas from Azerbaijan to the world pass close to Nagorno-Karabakh. Armenia also warned about security risks in the South Caucasus in July after Azerbaijan threatened to attack Armenia’s nuclear power plant as possible retaliation.
Nagorno-Karabakh broke away from Azerbaijan in a conflict that broke out as the Soviet Union collapsed in 1991.
Though a ceasefire was agreed in 1994, after thousands of people were killed and many more displaced, Azerbaijan and Armenia frequently accuse each other of attacks around Nagorno-Karabakh and along the separate Azeri-Armenian frontier.