The Interstate Aviation Committee (IAC) has not been approached to help decode the flight data recorders of the sunken Russian military plane in the Black Sea but stands ready to assist.

"So far [the experts] have not been approached. If the Defense Ministry wishes to involve us in the investigation, then of course we will render all possible assistance," the official said. The main recorder found earlier in the day is expected to be sent to the central research institute in southeastern Moscow for decryption in the coming hours.

The Russian Defense Ministry's Tu-154 aircraft en route to Syria from Moscow crashed soon after takeoff near Russia's Black Sea resort of Sochi early on Sunday.

The plane was carrying 92 people including eight crew members, 64 musicians of the Alexandrov Ensemble, nine reporters, head of Spravedlivaya Pomoshch (Fair Aid) charity Elizaveta Glinka, and two federal civil servants.