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.

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

The leader of Azerbaijan criticized the Russian response to the crash of a passenger jet that Azerbaijani officials said had most likely been hit by Russian air defenses.

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.

Flight J2-8243 crashed on Wednesday in a ball of fire near the city of Aktau in Kazakhstan after diverting from southern Russia, where Ukrainian drones were reported to be attacking several cities. At least 38 people were killed in the crash while 29 survived.

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.

Azerbaijani President Ilham Aliyev says Russia shot down one of his country's passenger planes "by accident" last week.

Azerbaijan’s President Ilham Aliyev said on Sunday that the Azerbaijani airliner that crashed in Kazakhstan on Wednesday, killing 38 people, was shot down by Russia, albeit unintentionally. Aliyev

Azerbaijani leader Ilham Aliyev is demanding answers, saying Vladimir Putin's latest apology "isn't enough" and that Moscow must take responsibility.

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.”