RFE/RL -- The Russian and Armenian governments have finalized a far-reaching agreement that will prolong and upgrade Russian military presence in Armenia, a diplomatic source in Yerevan said on Friday.

The source told RFE/RL’s Armenian service that the two governments have worked out corresponding amendments to a 1995 treaty regulating the presence of a Russian military base in the country. They are likely to be signed during Russian President Dmitry Medvedev’s visit to Armenia next week, he said.

The amendments will extend Russia’s basing rights by 24 years, to 2044, and upgrade the mission of its troops headquartered in Gyumri. The Interfax news agency reported on July 30 that a relevant “protocol” submitted to Medvedev by the Russian government makes clear that the troops will have not only “functions stemming from the interests of the Russian Federation,” but also “protect Armenia's security together with Armenian Army units.” It also commits Russia to supplying its regional ally with “modern and compatible weaponry and special military hardware.”

Some Armenian opposition figures and commentators have expressed concern about the planned changes to the treaty, saying that they could make Armenia even more dependent on Russia. Giro Manoyan, a senior member of the opposition Armenian Revolutionary Federation (Dashnaktsutyun), said on Friday that the changes will be “worrisome” as long as the Armenian government has not convincingly explained their rationale.

“My impression is that Russia has found an opportune moment to clinch from Armenia an extension of its basing rights in return for satisfying some of Armenia’s demands,” Manoyan told a news conference.

But Razmik Zohrabian, a deputy chairman of President Serzh Sarkisian’s Republican Party (HHK), defended the deal, saying that it will strengthen Armenia militarily and deter Azerbaijan from “unleashing a new war.” He claimed that the new mandate of the Russian base would oblige Moscow to support the Armenian side in case of renewed fighting in Nagorno-Karabakh.

“If war again breaks out between Karabakh and Azerbaijan, Armenia will naturally directly intervene, and if Armenia has the right to use the Russian base for its security, it means that Russia has to join the war on Armenia’s side,” Zohrabian told RFE/RL.

Commenting the agreement’s reasons and timing, Zohrabian suggested that Moscow is seeking to secure its long-term military presence in Armenia and keep the latter from joining NATO in the foreseeable future. “Perhaps the Russians have a sense that Armenia may seek to join NATO,” he said. “And that is normal, if they want to retain and strengthen their influence in this region.”