A Syria-bound Russian military plane crashed into the Black Sea Sunday, with no sign of survivors among the 92 on board, including Red Army Choir members travelling to celebrate New Year with troops.
The Tu-154 plane went down shortly after taking off from the southern city of Adler where it had been refuelling, defence ministry spokesman Igor Konashenkov said.
It disappeared from radar just two minutes after it took off at 5:25 am (0225 GMT).
The ministry told agencies there was no sign of any survivors at the crash site and that 10 bodies had been recovered off the coast of the resort city of Sochi, as authorities pledged to dispatch an additional 100 divers to aid in the search.
"Fragments of the Tu-154 plane of the Russian defence ministry were found 1.5 kilometres (0.9 miles) from the Black Sea coast of the city of Sochi at a depth of 50 to 70 metres," the ministry said.
President Vladimir Putin told state television that Russia will observe a day of national mourning on Monday.
The plane had been on a routine flight to Russia's Hmeimim air base in western Syria, which has been used to launch air strikes in Moscow's military campaign supporting its ally President Bashar al-Assad in the country's devastating civil war.
Among the plane's 84 passengers were Russian servicemen as well as 64 members of the Alexandrov Ensemble, the army's official musical group also known as the Red Army Choir, and its conductor Valery Khalilov.
They were headed to Syria to participate in New Year celebrations at the air base.
There were also nine journalists and eight crew onboard.
Transport Minister Maxim Sokolov, in charge of a government probe into the crash, said on state television that investigators were looking into a "whole spectrum" of theories on the cause of the crash.
When asked if a terror attack could have been behind the crash, Sokolov said: "It is premature to speak of this."
He added that the aircraft's black boxes had yet to be located.
The defence ministry said the searches would go on round-the-clock with the help of ships equipped with searchlights.