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 on Saturday issued an apology for the Azerbaijan Airlines passenger jet crash in Kazakhstan that occurred earlier this week, but stopped short of claiming responsibility for it.

On Christmas Day, a plane traveling from Baku, Azerbaijan, to Grozny, Russia, crashed in Kazakhstan, killing over half of its passengers. Theories abound regarding why the plane made an emergency landing near the Kazakhstani city of Aktau.