The crisis in Nagorno-Karabakh has come amid a sharp deterioration in the relationship between historic allies Armenia and Russia, and has been amplified by sometimes incendiary commentary from prominent individuals in Moscow.

Azerbaijan said that it started anti-terrorist operations in the enclave, which has been the scene of months of tension.

Russian media reports on September 21 said that the deputy commander of Russia's North Fleet submarine forces, Captain First Rank (Colonel) Ivan Kovgan, was among Russian troops killed during Azerbaijan's shelling of the breakaway region of Nagorno-Karabakh a day earlier.