Kazakhstan and Russia recently announced an agreement to create a joint air defense network, during a visit of Russian Defense Minister Sergey Shoigu to Astana. From RIA Novosti:
Russia and Kazakhstan signed a deal on Wednesday to create a joint regional air defense system, Kazakhstan's Defense Ministry said on Wednesday.
“This document will create a platform to secure the defense of Kazakhstan’s airspace and Russia’s adjacent territory,” the Defense Ministry said in a statement....
Russia has previously had such an air defense agreement only with Belarus, but has planned to sign a similar one with Armenia, although the two countries do not share a border.
If that sounds familiar, the two sides announced the same thing two years ago. From RIA Novosti in December, 2010:
Russia and Kazakhstan have agreed to create a joint regional air defense network, chief of Kazakh air defenses Lt. Gen. Alexander Sorokin said on Wednesday.
"We have agreed to create a joint regional air defense network, which is similar to that of Russia and Belarus," Sorokin said, adding that the Kazakh Air Force would be responsible for defending Russian airspace along the border with Kazakhstan.
Except that, two years ago, the story continued:
"The creation of this network envisions free-of-charge deliveries of Russian S-300 air defense systems to Kazakhstan," the general said.
Since then, however, nothing more has been heard of the S-300s. I surveyed a few Russian military experts and none had heard of the systems being delivered, "which," as one said, "makes me think they were not delivered." So what happened? Given the opacity of both sides' militaries, we shouldn't hold our breaths about finding out much.