Some 60 members of the Russian Red Army Choir, performing above, died in a plane bound for Syria on Christmas Day. Russia blames pilot or technical error for plane crash that claimed 92 Officials exclude terrorism was to blame for crash of military plane bound for Syria.

The Russian military plane carrying 92 people, among them around 64 members of a well-known army choir, that crashed into the Black Sea on its way to Syria was unlikely to have been brought down by a terror attack, authorities said Monday.

"As far as we know, the major versions do not include the terrorist attack, so we assume that the cause of the crash could be either technical malfunction or pilot error," Transport Minister Maxim Sokolov, who is leading the investigation into the crash, said according to Russia's TASS wire service. But he said authorities would not rule anything out until the investigation was concluded.

TASS reported that a total of 84 passengers and eight crew were on the Soviet-era three-engine "Tu-154" airliner when it disappeared from the radar.

The first 10 bodies and 86 body parts have been airlifted to Moscow, as a mass search involving thousands continues for the remaining victims and the plane's black boxes.

The members of the Red Army Choir, also known as the Alexandrov Ensemble, were on their way to a Russian air base in Syria to entertain troops. Also on board were nine reporters from Russia's Channel One, Zvezda and NTV networks, military servicemen, and the executive director of the Spravedlivaya Pomoshch charity Elizaveta Glinka, also known as Dr. Liza.

Russian President Vladimir Putin announced on Sunday that the country would observe a national day of mourning on Monday in honor of the victims. Flags will fly at half-mast and cultural and entertainment activities will be canceled. Some television stations have also opted not to screen advertisements.

This story was updated to include new details.

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