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.

Experts say evidence in the Azerbaijan Airlines plane crash in Kazakhstan points to a possible midair explosion, not an encounter with a flock of birds.

Azerbaijan's flag carrier announced Friday that it will suspend flights to several Russian airports, citing potential flight safety risks after a crash of one of its planes that many experts blamed on Russian air defence fire.