With Azerbaijan's confirmation of its purchase of a new air defense system from Russia, the S-300, by displaying it at its Armed Forces Day parade in Baku a few weeks ago, it "instantly becomes the most capable SAM [surface-to-air missile] system in the region," writes air defense analyst Sean O'Connor in the latest edition of the IMINT & Analysis newsletter.

The most intriguing part of the sale is that Azerbaijan's foe, Armenia, is a strong military ally of Russia; Russia stations troops at a big base in Gyumri, Armenia, and supplies heavily discounted weapons to the Armenian forces (and by extension, the Armenians who control the breakaway Azerbaijani territory of Nagorno Karabakh). All that, no doubt, was part of the reason that Russia denied that the sale had taken place, only to be proven wrong in a flashy parade in central Baku:

Regardless of Russia’s motivations for keeping the sale out of the public eye, Rosoboronexport’s public denial of the contract represents an interesting occurrence. On one hand, Rosoboronexport’s implications may have been completely accurate if a complete contract did not exist at the time of announcement. Finalization of the contract and subsequent non-announcement to temper Armenian concerns represents a logical course of action in that regard. On the other hand, however, the following statement represents a factual description of the Azeri Favorit situation: the press reported a sale, Rosoboronexport denied a sale, and Rosoboronexport then delivered Favorit components to Azerbaijan.

This incident will serve to cast doubt upon any future denials of Russian military sales to foreign states, leaving observers to ask the question: “what is really going on?”

There is an ongoing debate about whether Russia, through the mechanism of the Collective Security Treaty Organization, would intervene on Armenia's side in the case of a war with Azerbaijan over Karabakh. If so, Russian missiles -- and more importantly, planes and pilots -- would then face the prospect of being shot down by Russian air defense systems. But O'Connor notices an interesting detail: the new systems will have a range large enough to cover Nagorno Karabakh, but not the Russian military base in northern Armenia:

Azerbaijan currently operates two S-200 (SA-5 GAMMON) batteries near Baku and Mingechaur; the S-300PMU-2 represents a logical replacement for these systems offering coverage of the majority of the nation. Furthermore, deployment of the Favorit batteries at S-200 complexes offers coverage of the entire Nagorno-Karabakh region and the bulk of Armenia, while conveniently leaving the Russian military complexes near Gyumri out of reach.