Increasing analysis suggests Russian air defenses might have downed Azerbaijan Airlines flight J2-8243, which crashed in a ball of fire near Aktau,Kazakhstan on Wednesday morning, killing 38 of 67 passengers and crew.

Azerbaijani President Ilham Aliyev has launched a criminal probe to uncover the reasons behind the plane crash.

Azerbaijan on Thursday observed a nationwide day of mourning for the victims of the plane crash that killed 38 people and left all 29 survivors injured as speculation mounted about a possible cause of the disaster, with some experts saying that the airliner was damaged by Russian air defense fire.

An international investigation has begun into how an Embraer 190 passenger jet with 67 people onboard crashed in Kazakhstan, killing 38 people but leaving 29 survivors Azerbaijan Airlines flight J28243,

Azerbaijan marked a somber Thursday after a state-owned passenger plane burst into flames after crashing in Kazakhstan, killing at least 38 people aboard.Azerbaijan held a national day of mourning Thursday,

National flags were lowered across Azerbaijan, traffic across the country stopped at noon, and signals were sounded from ships and trains as the country observed a nationwide moment of silence.

It comes as the head of Russia's civil aviation agency says the situation in Grozny, the plane's destination, was "very complicated" at the time.