By Guy Faulconbridge, Andrew Osborn and Nailia BagirovaMOSCOW/BAKU (Reuters) -President Vladimir Putin on Saturday apologised to Azerbaijan's leader for what the Kremlin called a "tragic incident" over Russia in which an Azerbaijan Airlines plane crashed after Russian air defences were fired against Ukrainian drones.

The Kremlin has said that Putin "apologized for the tragic incident" and expressed his "deep and sincere condolences" the the victims' families.

On 25 December, 38 people died when an Azerbaijan Airlines flight, which had been due to land in Russia, crash-landed in Kazakhstan. The circumstances around the crash remain unclear, but limited evidence so far suggests it may have been hit by missiles fired by a Russian air-defence system as it tried to land in Chechnya.