Russia has grounded all Tupolev-154 planes until it understands why one of the ageing Soviet planes crashed into the Black Sea on Sunday, killing all 92 on board, the Interfax news agency cited an unnamed source as saying.
Russian news agencies cited the Defence Ministry earlier reported that authorities had found one of the downed plane's flight recorders.
The Russian authorities have said pilot error or a technical fault caused the plane to crash shortly after take-off on a flight to Syria. Its passengers included a well-known army band and a group of journalists.