International envoys will meet on Tuesday to try to end fighting in the disputed Caucasus region of Nagorno-Karabakh. At least 36 people have reportedly been killed in the region and Armenia has warned of a possible descent into "full-scale war".
Azerbaijan said on Monday that three more of its troops died in clashes with ethnic-Armenian forces from Nagorno-Karabakh, which is internationally recognised as Azeri territory but has run its own affairs – with Armenia's support – for more than 20 years.
The Azeri losses took the reported death toll from fighting that erupted on Friday night to 36, including three civilians, in the worst violence to hit remote, mountainous Nagorno-Karabakh since a 1988-94 war that killed 30,000 people and displaced more than a million.
Azerbaijan and Nagorno-Karabakh blame each other for starting the latest fighting, which involves tanks, helicopters and heavy artillery rather than the sniper and mortar fire common along the so-called ceasefire line.
Russia, the United States and European Union have called for calm, and in Vienna on Tuesday envoys from the Organisation for Security and Co-operation in Europe's Minsk Group – which is chaired by the US, Russia and France – will discuss the fighting and seek ways to reduce tension in the south Caucasus.
The crisis is causing particular alarm because it comes at a time of sharply raised tension over the war in Syria between Russia and Turkey, who are the main backers of Armenia and Azerbaijan respectively.
Armenian president Serzh Sargsyan told ambassadors from OSCE states on Monday that Azerbaijan's unilateral ceasefire declaration on Sunday had been intended merely to deceive, and that Azeri troops continue to bombard Nagorno-Karabakh's forces.
Mr Sargsyan warned that continued fighting could prompt Armenia to officially recognise the independence of Nagorno-Karabakh, formalise its already considerable military aid to the region and even trigger a “full-scale war”.
“This would naturally affect safety and stability in both the southern Caucasus and Europe,” he said, saying the clashes wee the worst since 1994.
Azerbaijan's president Ilham Aliyev accused Armenia's troops of starting the fighting and continuing to attack despite the "ceasefire" declared by Azeri forces.
“None of the enemy’s provocations will remain unanswered,” he told a meeting of Azerbaijan’s security council.
“The sons of Azerbaijan are defending the homeland, fighting for their country and becoming martyrs. The memory of all our martyrs will live in our hearts forever,” Mr Aliyev was quoted as saying by Azeri media.
“Armenia does not want peace. Armenia does not want to vacate the occupied lands, and all of its efforts are aimed at maintaining the status quo,” he added.
Turkish president Recep Tayyip Erdogan said at the weekend that his country would support Azerbaijan "to the end" and expressed hopes that "our Azerbaijani brothers will prevail in these clashes with the least casualties".
Russia, meanwhile, supplies weapons to both Muslim Azerbaijan and Christian Armenia but has much closer ties with the latter, and maintains an army base and an airbase with attack jets and helicopters on Armenian territory.