Russians who reviewed the transcript of the crew's conversations from the Baku-Grozny flight themselves admit that the air crash was caused by their air defense systems (ADS), according to Andriy Kovalenko,

Russian President Vladimir Putin apologized to his Azerbaijani counterpart for what he called a "tragic incident" following the crash of an airliner.

Azerbaijani President said Sunday that the plane that crashed in Kazakhstan on Wednesday "was damaged from outside on Russian territory."

Russia has published a festive video of Santa Claus becoming a victim of Russian air defence against the backdrop of the tragic crash of an Azerbaijan Airlines passenger plane in Grozny, with growing evidence pointing to Russian air defence as the cause.

Azerbaijani President Ilham Aliyev on Sunday demanded that Russia admit that it fired at an Azerbaijan Airlines passenger jet before it crashed, accusing Moscow of initially trying to cover up the cause of the fatal disaster.

Two U.S. military officials told NBC News that they had intelligence indicating that Russians may have misidentified the plane and shot it down.

The probe into the Azerbaijan Airlines crash in Kazakhstan is examining the conduct of air traffic controllers after the aircraft encountered difficulty, a source said.

Azerbaijan’s President Ilham Aliyev has accused Russia of accidentally shooting down an airliner on Christmas Day in a disaster that killed 38 people, and covering up the cause.

"We can clearly say today that the plane was shot down by Russia," President Ilham Aliyev said in a televised statement