Armenia and the U.S. started holding joint military drills near the capital Yerevan on Monday, angering Russia.

The "Eagle Partner" war games will run through Sept. 20 and involve 175 Armenian and 85 troops. They reflect Armenian Prime Minister Nikol Pashinyan's efforts to forge closer ties with the United States and other Western allies amid the simmering tensions with neighboring Azerbaijan.

The Armenian Defense Ministry said that the drills are aimed at increasing interoperability of units participating in international peacekeeping missions and exchanging tactical skills.

Moscow has reacted with dismay. On Friday, the Russian Foreign Ministry summoned the Armenian ambassador to lodge a formal protest over the exercises and other moves by Armenia that it described as "unfriendly."

Russia has been Armenia’s main economic partner and ally since the 1991 Soviet collapse. Landlocked Armenia hosts a Russian military base and is part of the Moscow-led security alliance of ex-Soviet nations, the Collective Security Treaty Organization.

But Pashinyan has become increasingly critical of Moscow's role, emphasizing its failure to help lift what Armenia called the blockade in Karabakh and arguing that Armenia needs to turn to the West to help ensure its security.

Karabakh is a region within Azerbaijan that came under the control of ethnic Armenian forces backed by the Armenian military after a six-year separatist war that ended in 1994. Armenian forces also took control of substantial territory around the region.

Azerbaijan regained control of the surrounding territory and a significant part of Nagorno-Karabakh in a six-week war with Armenia in 2020. A Russia-brokered truce that ended the war left the region connected to Armenia by just one road known as the Lachin Corridor, along which were supposed to ensure free movement.

Speaking to reporters on Monday, Kremlin spokesman Dmitry Peskov rejected the Armenian authorities' claims that Moscow wasn't doing enough to protect its ally and noted that Armenia's decision to hold joint war games with the U.S. requires a "deep analysis."

At the same time, Peskov sought to play down the differences between Russia and Armenia, saying that "we will remain close allies and partners."

"We may have certain problems that need to be solved through dialogue, because the logic of our development and national interests of both countries determine the necessity to further deepen our alliance and partnership," he said.