A Russian military plane with 91 people on board has crashed into the Black Sea and debris from the plane has been found in the sea near Sochi, media reports said.

The plane disappeared from radar 20 minutes after taking off from Adler airport in the resort of Sochi at 05:20 (02:20 GMT), said a BBC report.

The Russian defence ministry said the Tu-154 aircraft was carrying service personnel, members of the famed Alexandrov choir and reporters.

The plane was reportedly flying to Syria's Latakia province.

Russian defence ministry spokesperson Igor Konashenkov said the plane was carrying passengers to a New Year's performance for Russian troops deployed in Syria.

Russia - a key ally of Syrian President Bashar al-Assad - has been carrying out air strikes against what it described as terrorist groups.

The aircraft went missing as it was manoeuvring over Russia's territorial waters, a source at the emergency ministry was quoted as saying by Russian news agencies.