One possibility that comes to mind: Agri is almost on the border with Armenia, and the reason for its militarization is the long standoff between Turkey and Armenia (the border has been mostly closed since 1989). It might be an Armenian tactic to launch a fake mass garbage-dialling campaign as a way of provoking an indirect denial-of-service attack against Agri. (Can't see how it would work, the Turkish military doesn't depend on the phone service).

Or perhaps more likely, since Turkey and Armenia have been having some sort of rapprochement in recent months, it might be some nationalist fringe group from either country trying to sow bad feeling.