The leadership in Moscow on Friday refused to comment on claims that a Russian missile had caused Wednesday's crash of an Azerbaijan Airlines passenger jet in Kazakhstan with the loss of 38 lives. Moscow was aware of statements made in Azerbaijan's capital Baku,

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."

After 38 people died in the crash, some experts said the plane may have been accidentally shot by Russian air defense systems in an area where Ukrainian drone activity had been reported.

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.

Russian President Vladimir Putin apologized for the deadly Azerbaijan Airlines Flight 8243 crash on Christmas but did not take responsibility for causing it as an investigation continues into the matter.