Plane crash probe in Kazakhstan underway as speculation mounts about possible Russian involvement [Video]

Azerbaijan on Thursday observed a nationwide day of mourning for the victims of the plane crash that killed 38 people and left 29 survivors injured, as speculation mounted about the cause of the disaster — including whether possible Russian air defense operations may have played a role.

Azerbaijan Airlines’ Embraer 190 was en route from Azerbaijan’s capital of Baku to the Russian city of Grozny in the North Caucasus on Wednesday when it was diverted, for reasons that are still unclear, and crashed while trying to land in Aktau, in western Kazakhstan, after flying east across the Caspian Sea. The plane went down about 2 miles from Aktau.

A U.S. official told CBS News there are early indications a Russian anti-aircraft system may have struck the plane. The official, who asked not to be publicly identified, said that if these indications prove true, it would further underscore Russian recklessness in its invasion of Ukraine.

Cellphone footage circulating …