MOSCOW -- The flight recorders of the Russian military Tu-154 aircraft that crashed into the Black Sea on Sunday could remain intact, a senior official was quoted as saying on Monday.

"Flight recorders will definitely be raised when the plane is found on the sea floor, we know where they are; they are in the fin," the Interfax news agency quoted Russian Airspace Forces Commander-in-Chief Viktor Bondarev as saying.

Bondarev believed that the flight recorders, also known as black boxes, could be intact since the fin is normally the least damaged part in an air accident.

Currently, 3,500 people are participating in the search and recovery operation, as well as 39 ships, and seven deep-sea submergence vehicles, according to the Russian Defense Ministry.

So far, 11 bodies and 154 fragments have been recovered, of which 10 bodies and 86 fragments were sent to Moscow by plane for identification, the Defense Ministry said.

Russian Deputy Defense Minister Pavel Popov was quoted as saying at a briefing in Sochi that experts believed the aircraft had fallen into the sea some 6 km away from the shore.

Meanwhile, Transport Minister Maksim Sokolov virtually ruled out the possibility of a terror attack behind the tragedy.

"The main versions of the crash may be technical failures or pilot errors," Sokolov told a press briefing broadcast live by the Russia 24 TV channel.

The exact causes have yet to be established by investigators and a special commission of the Russian Defense Ministry.

The ill-fated plane, en route to Russia's Hmeimim air base in the Syrian port city of Latakia, crashed shortly after takeoff from Sochi early Sunday morning.

Ninety-two people -- 84 passengers and eight crew members -- were aboard the plane. Most of them were members of the Alexandrov Ensemble, a renowned choir of the Russian Armed Forces, as well as nine Russian journalists. They were heading to the air base for New Year celebrations.