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.

It comes as the head of Russia's civil aviation agency says the situation in Grozny, the plane's destination, was "very complicated" at the time.

The plane, which crashed in Kazakhstan this week, went down “due to external physical and technical interference,” according to the investigation’s preliminary findings.