The fighting has killed at least one Azerbaijani soldier, according to that country’s foreign ministry on Wednesday.
The Armenian Foreign Ministry also said the clashes left “some dead and injured”, but did not specify how many or which side they belonged to. He also called on the world to intervene to end Azerbaijan’s “aggressive behavior and actions”.
Kremlin spokesman Dmitry Peskov told reporters that Russia was “concerned”, Reuters reported.
“We are monitoring very closely, we are understandably concerned about the worsening of the situation,” he said on Thursday. “We ask the parties to show restraint and above all to implement all the provisions of the trilateral documents.”
Both sides accused the other of launching attacks against military positions in Nagorno-Karabakh.
Russia, an Armenian security ally, maintains a peacekeeping force in the region after brokering a ceasefire agreement in early November 2020, ending a nearly two-month conflict that has killed in least 6,500 people, according to Reuters.
On Wednesday, the Russian Defense Ministry also accused Azerbaijani forces of violating the ceasefire, Russian news agency TASS reported.
“The command of the Russian peacekeeping contingent, together with representatives of the Azerbaijani and Armenian sides, are taking steps to stabilize the situation,” the ministry said in a statement, according to TASS.
On Wednesday, the European Union called for an immediate cessation of hostilities.
“It is essential to de-escalate, fully respect the ceasefire and return to the negotiating table to seek negotiated solutions,” an EU spokesperson said in a statement.
Nagorno-Karabakh is populated and controlled by ethnic Armenians, and aided by the Armenian diaspora.
It lies inside Azerbaijani territory and is connected to nearby Armenia by an expensive highway, known as the Lachin Corridor, where Wednesday’s clashes took place.
Azerbaijan has long claimed it will take back the territory, which is internationally recognized as Azerbaijani. Control of the area became a point of nationalist pride in both countries.
The unrest in Nagorno-Karabakh dates back to the collapse of the Soviet Union, when the region, backed by Armenia, declared independence from Azerbaijan.