Azerbaijan’s leader on Monday accused Moscow of carrying out a “cover up” over a passenger jet crash last month that claimed 38 lives, as relations sour between the two neighbors.

Azerbaijan’s President Ilham Aliyev says the Azerbaijani airliner that crashed last week was shot down by Russia, albeit unintentionally.

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.

Russian President Vladimir Putin apologized for the “tragic incident,” which left 38 people dead, though he stopped short of taking responsibility.

Azerbaijan President Ilham Aliyev said Russia is behind the Christmas Day crash of an Azerbaijan Airlines plane in Kazakhstan, which killed 38 of the 67 people aboard. The motives of the incident remain unclear.

"Unfortunately, in the first three days we heard only absurd versions from Russia," President Ilham Aliyev said, citing statements in Russia that attributed the crash to a bird strike or the explosion of some sort of gas cylinder.

Four sources with knowledge of the preliminary findings of Azerbaijan's investigation told Reuters that Russian air defences mistakenly shot it down.

In the crash’s aftermath, Azerbaijan has unleashed rare and stinging criticism of Russia, with the country’s president saying Moscow’s response has caused “surprise, regret and rightful indignation.”

Azerbaijan's president has confronted Putin over the devastating plane crash that killed 38 people on Christmas Day.