Thursday is an official day of mourning in Azerbaijan as an investigation is underway to determine what caused an airplane carrying 67 passengers to crash on Christmas Day in Kazakhstan, killing 38 and leaving at least 29 survivors.

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.

We demand justice, we demand punishment for those responsible, and we demand full transparency, — said the President of Azerbaijan, Ilham Aliyev, regarding the plane crash caused by a Russian missile.