The Azerbaijan Airlines plane flew hundreds of miles off its scheduled route from Baku to Grozny, and crashed on the eastern shore of the Caspian Sea. Russia's aviation watchdog said a bird strike might have been the cause.

A day after an Azerbaijani airliner’s crashed in Kazakhstan, aviation experts say the plane most likely went down after being hit by Russian air defense systems.

The flight was en route from the Azerbaijani capital of Baku to Grozny, in Russia’s south, when it diverted and attempted an emergency landing in Kazakhstan.

The preliminary results of Azerbaijan’s investigation into the deadly crash of a civilian airliner point to the plane being hit by a Russian antiaircraft missile, or shrapnel from it, said people briefed on the probe.

The cause of a deadly plane crash in southwestern Kazakhstan is being investigated, and some officials are claiming Russian involvement.

There are early indications that a Russian anti-aircraft system may have struck the Azerbaijan Airlines plane that crashed in Kazakhstan, a U.S. official told ABC News.

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.

Thirty-eight of 67 onboard flight from Baku to the Chechen city Grozny believed to have been killed. Russian authorities cite bird strike.