The statement is the closest officials have come to confirming mounting suspicions that the plane was downed by a Russian air-defense system.

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.

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.