Defense officials in the disputed territory of Nagorno-Karabakh have accused Azerbaijan of attacks that left two ethnic Armenian soldiers dead.
A statement from the Nagorno-Karabakh Defense Ministry said Azerbaijani infiltrators crossed the buffer zone that separates the region from the rest of Azerbaijan early on January 3 and opened fire.
Armenia warned Azerbaijan of consequences in case of more attacks.
The Azerbaijani Defense Ministry denies entering the territory.
Nagorno-Karabakh is located within Azerbaijan's borders but is inhabited almost entirely by ethnic Armenians.
A 1994 truce ended six years of bitter fighting between the two sides, but both sides frequently claim attacks despite the cease-fire.