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.

The Azerbaijan Airlines plane that crashed experienced "external physical and technical interference," the airline says.

U.S. and Azerbaijani officials have said weapons fire may have brought down an Azerbaijani airliner that crashed on Wednesday, killing 38 people

National flags were lowered across Azerbaijan, traffic across the country stopped at noon, and signals were sounded from ships and trains as the country observed a nationwide moment of silence.