The cause of the crash of Azerbaijan Airlines flight J2-8243 near the city of Aktau, Kazakhstan, is still unknown. The Kremlin has so far been tight-lipped, prompting questions over its messaging.

White House national security spokesman John Kirby told reporters that the US “have seen some early indications" that the plane was "brought down by Russian air defense systems."

An Azerbaijani minister suggested Friday that an airliner that crashed this week was hit by a weapon, citing expert analysis and survivor testimony indicating that the plane was struck from the outside.

Azerbaijan’s transport minister has said that the passenger plane that crashed on Christmas Day in Kazakhstan, killing 38 people, was hit by some “type of weapon”. This comes as United States military sources suggest that the Azerbaijan Airlines flight was shot down by Russian air defences believing it to be a drone.

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.

"No one claims that it was done on purpose," an Azerbaijan official told Reuters. They added their government "expects the Russian side to confess."

Two U.S. military officials tell NBC News the U.S. has intelligence indicating that the Russians may have misidentified the Azerbaijan Airlines flight that went down earlier this week, and shot it down with an air defense system.