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.

Azerbaijan held a day of mourning on Thursday for the dozens of victims of an airliner crash in Kazakhstan, as questions were being asked over the cause of the disaster.

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.