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.

The U.S. government suggested Friday that Russia may be to blame for this week’s deadly Azerbaijan Airlines crash, echoing experts’ assessment of the tragedy as investigations remain ongoing. Azerbaijan Airlines Flight 8243 was scheduled to travel from Baku,

The White House said Friday there were "early indications" that Russian air defenses downed an Azerbaijan Airlines flight in Kazakhstan.

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.

Azerbaijan Airlines says the jet that crashed in Kazakhstan on Christmas Day experienced “physical and technical external interference,” according to an early investigation, as questions swirled about Russia’s possible involvement in the disaster.

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

Russia won't say if it mistakenly downed an Azerbaijani plane on Christmas. But it acknowledges the crash came amid a Ukrainian drone attack in its republic of Chechnya.

Experts say evidence in the Azerbaijan Airlines plane crash in Kazakhstan points to a possible midair explosion, not an encounter with a flock of birds.