Heavy fighting has been reported in Nagorno-Karabakh, a disputed region in Azerbaijani territory with a predominantly Armenian population.
The Armenian military has accused Azerbaijan of mounting a major offensive, involving tanks, heavy artillery, and helicopters, Radio Free Europe reported.
Baku, in turn, has claimed that Azerbaijani troops acted in self-defense.
Casualties have been reported on both sides.
Kremlin spokesman Dmitry Peskov said, “President Putin urges the parties to the conflict to enact an immediate ceasefire and exercise restraint in order to prevent further human casualties.”
The Russian Foreign Ministry has started consultations with the OSCE Minsk Group on the situation in Nagorno-Karabakh, which is co-chaired by France, Russia, and the United States.
US Vice President Joe Biden met with the leaders of Armenia and Azerbaijan separately on April 1st and urged them to peacefully settle the conflict.
The de facto independent and unrecognized Nagorno-Karabakh Republic was established on the basis of the Nagorno-Karabakh Autonomous Oblast of the Azerbaijan Soviet Socialist Republic and has been controlled by ethnic Armenians since a war over the disputed territory ended in 1994.