The already strained relations between Russia and Armenia have significantly deteriorated following a diplomatic dispute over Armenia's response to Moscow's all-out invasion of Ukraine.

The diplomatic rift arose after Armenian officials visited the Ukrainian town of Bucha, which prompted Russia to send a protest note to Armenia's Foreign Ministry, wrote Russian Foreign Ministry spokeswoman Maria Zakharova on Telegram on Sunday evening.

The visit to Bucha was a "frankly unfriendly step," Zakharova wrote.

Bucha, a Kyiv suburb, gained international attention when the bodies of more than 400 civilians allegedly massacred by the Russian troops were discovered there after Moscow's withdrawal in the spring of 2022.

During a visit to Bucha a few days ago, an Armenian delegation assured Kyiv of its solidarity "against Russian aggression." The delegation included Armenia's ambassador in Kyiv, Vladimir Karapetyan.

Historically, Russia has been seen as a protector of Armenia and maintains a military base there. However, relations have cooled since the pro-Western Prime Minister Nikol Pashinyan came to power in Yerevan.

Armenia has felt abandoned by Russia, especially during its conflict with Azerbaijan over the Nagorno-Karabakh region.

Following its defeat in a major offensive by Azerbaijan in Nagorno-Karabakh last year, Armenia has increasingly questioned its membership in the Moscow-dominated military alliance, the Collective Security Treaty Organization (CSTO).