A Russian military plane with 92 people on board has crashed into the Black Sea on its way to Syria, Russian news agencies reported on Sunday, and it was unlikely there would be any survivors.

Russian agencies, citing unnamed security sources, said the TU-154 aircraft had crashed in the sea near the southern Russian city of Sochi after disappearing from radar screens.

The plane was carrying Russian servicemen and members of a renowned military choir and dance ensemble, the Alexandrov Ensemble, who were being flown into Russia's Hmeymim air base in Syria to entertain military personnel in the run-up to the new year, the RIA news agency quoted the Defence Ministry as saying.

The plane was carrying 84 passengers and eight crew members, agencies quoted the ministry as saying. Nine Russian reporters were among the passengers, agencies said.

Fragments of the plane have already been found at a depth of 50-70 metres at a distance of around 1.5 kilometres (0.93 miles)from the Russian coast, agencies reported

Russia's RIA news agency, citing an unidentified security source, said preliminary data indicated that the plane had crashed because of a technical malfunction or a pilot error.

The Interfax news agency cited an unnamed source as saying the plane had not sent an SOS signal.

Kremlin spokesman Dmitry Peskov told reporters on Sunday it was too early to say what had caused the crash. President Vladimir Putin was being kept informed of latest developments, Peskov added.

Russia's Defence Ministry regularly flies musicians into Syria to put on concerts for military personnel. The base they were heading for, Hmeymim, is in Latakia province. It is from there that Russia flies air strikes against Syrian rebels.

Earlier in December, another Russian Defence Ministry crashed in Siberia with 39 people on board as it tried to make an emergency landing near a Soviet-era military base. Nobody was been killed in that incident, though 32 people were airlifted to hospital.