Russia on Wednesday accused Azerbaijan of breaking a ceasefire over the disputed region of Nagorno-Karabakh after three soldiers died in clashes with what Baku called "illegal Armenian armed groups."
Six weeks of fighting over the region in the autumn of 2020 claimed more than 6,500 lives and ended with a Russian-brokered ceasefire agreement.
The Russian defense ministry issued a statement saying Azerbaijan's armed forces violated the ceasefire and that it was "taking measures to stabilize the situation" with Armenian and Azerbaijani representatives.
Azerbaijan's defense ministry had earlier said Karabakh troops killed one of its soldiers in an attack in the Lachin district, blaming Armenia for the "bloody incident."
The Azerbaijani army later said it had captured several strategic heights in the region in a retaliatory operation against the "terrorist actions of illegal Armenian armed groups on the territory of Azerbaijan."
The army of the breakaway statelet accused Azerbaijan of violating the ceasefire, killing two soldiers and wounding another 14.
Arch enemies Armenia and Azerbaijan fought two wars – in 2020 and in the 1990s – over Azerbaijan's Armenian-populated region of Nagorno-Karabakh.
Armenia ceded swathes of territory it had controlled for decades, and Russia deployed some 2,000 peacekeepers to oversee the fragile truce, but tensions persist despite a ceasefire agreement.