The Azerbaijan Airlines plane flew hundreds of miles off its scheduled route from Baku to Grozny, and crashed on the eastern shore of the Caspian Sea. Russia's aviation watchdog said a bird strike might have been the cause.

Moscow officials have not addressed statements from aviation experts who blamed the crash on Russian air defenses responding to a Ukrainian attack.

BAKU (Reuters) -Russian air defences downed an Azerbaijan Airlines plane that crashed in Kazakhstan, killing 38 people, four sources with knowledge of the preliminary findings of Azerbaijan's investigation into the disaster told Reuters on Thursday.

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.

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 has accused Russia of shooting down a plane that recently crashed under controversial circumstances. The allegation comes amid heightened tensions in the region, with both countries exchanging accusations over security and sovereignty issues.