Moscow will loan Armenia $200 million (€180 million) to purchase advanced Russian heavy arms, officials in Yerevan said on Thursday.
The loans will have a maturity of 13 years with a three-year grace period and three percent interest rate per year.
"We are acquiring kinds of weapons which have not been at the disposal of the Armenian armed forces previously," Armenia's deputy defence minister Ara Nazaryan told a parliament session on Thursday.
"Armenian armed forces will get new modern arms, which will have a substantial impact on balancing forces in the region."
No information has been released about type of weaponry that will be provided.
Armenian opposition members have criticised the government’s deal with Russia, implying that Kremlin is pushing Yerevan into an arms race with Azerbaijan because of a land dispute.
"Armenia is now forced to take a Russian loan to restore military balance in the region,” Zaruhi Postanjyan, opposition MP from the Heritage party said in parliament on Thursday.
"Russia is selling super-modern weapons to Armenia's enemy Azerbaijan and thus is dragging Armenia into an arms race."
Azerbaijani President Ilham Aliyev in 2013 stated that military and technical cooperation between his country and Russia was measured as being worth $4 billion and would grow further.
In 2014, Azerbaijan signed a deal with Moscow worth almost $1 billion providing heavy material and offensive weapons including armoured vehicles, conventional artillery and multiple rocket systems, 24 Mi-35 attack helicopters and 60 other helicopters.
Recently because of Russia’s annexation of Crimea and support for separatists in Ukraine, NATO has deployed weaponry on Eastern European soil to protect its member states and allies.
Armenia has a border with NATO ally Turkey with whom it has historical and border disputes.
Armenia is also in a land dispute with Azerbaijan over the territory of Nagorno (Northern) Karabakh, most of which has been occupied by Armenia since 1994.
In the 1990s, the Nagorno Karabakh conflict left 30,000 people dead.
The most dramatic massacre in the conflict occurred in February 1992 when Armenian and some CIS (Commonwealth of Independent States) forces killed at least 161 ethnic Azeri civilians in the Khojaly Massacre.
Russia has economic as well as strategic reasons for supporting Armenia, as many gas pipelines bringing Russian gas to the region run through Armenia.
Deputy Energy Minister Ara Simonian has said the Armenian government and Gazprom have already signed a tentative agreement on the sale of the Meghri-Kajaran section of one pipeline to Iran, Radio Free Europe’s Armenian news service reported on Wednesday.
The section is located in southeastern Armenia and runs for 41-kilometers up to the Iranian border to transfer natural gas to Iran.
The rest of the pipeline, completed in 2008, is already owned by Gazprom Armenia.
Another aspect of Russian influence in Armenian affairs can be seen in governmental issues. Russia keeps a close watch on Armenian civil movements and Armenia’s response to them.
For nearly two weeks thousands of Armenians have protested increased electricity tariff prices.
Russian Foreign Minister Sergei Lavrov has warned Armenia over the politicisation of the Yerevan protests, reminding people of the Ukrainian revolution.
"You know how the 'colour revolutions', and the Maidan in Ukraine, started," said Lavrov on Thursday at a Brazil, Russia, India, China and South Africa (BRICS) Youth Summit in Moscow.
"The current developments in Armenia - there is also a temptation among many to use them to whip up anti-government sentiment although the root of these events is purely economic," The Moscow Times reported Lavrov as saying.