Well, what do you know? The Federation considers Khitomer to be within the Romulan sphere of influence, if not Romulan territory outright.
Maybe the Klingons
were the aggressors prior to the 2340s, and managed to take and hold it long enough to settle a colony...and then the Romulans managed to drive the Klingons off Khitomer.
I wonder if Narendra III is Klingon or Romulan territory.