The commander of Russia's troops in Armenia has said those troops could be used in a conflict with Azerbaijan over Nagorno Karabakh, the first time that a Russian officer has publicly made such a claim. The commander of Russia's 102nd military base, Colonel Andrey Ruzinsky, made the comments in an interview with the Russian military newspaper Krasnaya Zvezda (via RFE/RL):

“If Azerbaijan decides to restore jurisdiction over Nagorno-Karabakh by force the [Russian] military base may join in the armed conflict in accordance with the Russian Federation’s obligations within the framework of the Collective Security Treaty Organization (CSTO)."

It's never been entirely clear how Russia would see the collective security provisions of the CSTO in the event of a conflict over Karabakh. While they would seem to clearly obtain if Azerbaijan attacked Armenia itself, since Karabakh is in de jure Azerbaijani territory, one could easily imagine Russia saying that a conflict restricted to that territory would be none of its business. But there really isn't any room for interpretation there, and this seems like a clear Russian shot across Azerbaijan's bow.

Azerbaijan took a while to respond, prompting the opposition news agency Turan to criticize official Baku for ignoring Col. Ruzinsky's statement. But when Baku finally did respond, it naturally, blamed Armenia:

“No treaty envisages the involvement of the Russian base into the hostilities in Nagorno Karabakh on Armenian part”, MP and political scientist Rasim Musabayov....

"I believe that this is the Armenian interpretation of the statement of the Russian military. The Russian colonel can also be just incompetent or bribed by Armenians and can say things that are beyond his powers”, the political scientist said.

And in a commentary on Vesti.az, Barkham Batyev described the reaction in Yerevan to the colonel's comments as the "screeching" of "squealing pigs" and, not without reason, sees it as a calculated attempt to pressure Baku:

The interview can be considered as a threat against Azerbaijan: don't even think of regaining Karabakh by force, at least before the end of the Sochi Olympics. Or, as a request in disguise: guys, our military industry is dying, please buy a few dozen pieces of military hardware, or two or three air defense systems and we'll allow you to recover your jurisdiction.

But in Moscow they have somehow forgotten that Azerbaijan doesn't have to ask anyone's permission when and how it wants to carry out a counterterror operation to restore jurisdiction over Karabakh and this is not the beginning of the 90s or even August, 2008. And the double standard of this type of interview encourages aggression, inflames animosity and prevents the peaceful resolution of the Armenian-Azerbaijan conflict, Moscow also has forgotten. And still, one desperately wants to believe that the leadership in RUssia is not so stupid and divorced from reality to participate in aggression against Azerbaijan...

The second part of that, the blustering against Russia, is not likely to convince anyone in the Kremlin. But the first part could definitely be valid, and that Col. Ruzinsky's statements are merely an attempt to threaten Azerbaijan. But that also suggests that, should conflict break out, Russia may well decide it's worth it to intervene against Azerbaijan.