Armenian Prime Minister Nikol Pashinyan has formally asked Russian President Vladimir Putin to begin "urgent" consultations on providing security amid a conflict with Azerbaijan, the foreign ministry said Saturday.
The announcement, which further raises the prospect of an escalation in the conflict, came after Armenia and Azerbaijan failed to agree a fresh ceasefire in Nagorno-Karabakh conflict during talks in Geneva on Friday.
Russia has a military base in Armenia and has a defence treaty with Yerevan.
"The prime minister of Armenia has asked the Russian president to begin urgent consultations with the aim of determining the kind and amount of aid which the Russian Federation can provide Armenia to ensure its security," the ministry said in a statement.
Azerbaijan and Armenia have been locked in a bitter conflict over Karabakh since Armenian separatists backed by Yerevan seized control of the mountainous province in a 1990s war that left 30,000 people dead.
The current clashes broke out on September 27 and fighting has persisted despite the repeated international attempts to secure a ceasefire.
Russia has previously said that its defence pact with Armenia does not extend to the breakaway region of Nagorno-Karabakh.
But Pashinyan in his letter to Putin said that hostilities were getting closer to Armenia's borders and reiterated that Azerbaijan's ally Turkey was backing Baku, according to the statement.
He requested Moscow's help, invoking the two countries' close ties and a 1997 treaty on friendship, cooperation and mutual assistance.
The warring sides have three times agreed to ceasefires during talks mediated by Russia, France and the United States but the truces have all quickly fallen apart.
More than 1,200 people from both sides have been reported dead since the fighting began, but the actual death toll is believed to be substantially higher.