President Vladimir V. Putin of Russia told the Azerbaijani leader, Ilham Aliyev, in a phone call, “that the tragic incident took place in Russian airspace.”

Russian President Vladimir Putin apologized for the plane crash in Russian air space on Christmas Day that left 38 people dead in a statement that said Russia was targeting Ukrainian drones over the plane’s planned destination at the time, but stopped short of taking responsibility.

After an Azerbaijan Airlines jet crashed in Kazakhstan, speculation mounted about why the plane went down and whether possible Russian air defense action may have played a role.