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.

"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.

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.”