Russia is reported to have grounded its Tu-154 planes until the cause of the crash in the Black Sea in which 92 people were killed has been identified.

According to the Ifax news agency, Moscow has suspended all Tupolev-154s until it understands why one of the ageing Soviet planes crashed. The Russian military has retrieved the flight recorder from the plane that went down two minutes after taking off from the southern Russian city of Sochi on Sunday.

Among the plane’s 84 passengers were dozens of singers from Russia’s world-famous military choir heading to the Russian Hmeymim airbase in Latakia, Syria, to perform at a New Year concert. The defence ministry said in a statement that one of the flight recorders was found early Tuesday morning about a mile away from the shore.

State television showed footage of rescue workers on an inflatable boat carrying a container with a bright orange object submerged in water. The ministry said the black box would be immediately flown to Moscow. It did not mention whether the flight recorder had sustained any damage.

Mourners on Tuesday continued to bring flowers to the pier of Sochi’s seaport as 3,500 people, 45 ships and 192 divers swept a vast area for bodies of the victims and debris.

Rescue teams so far have recovered 12 bodies and numerous body fragments, which have been flown to Moscow for identification. Divers found fragments of the fuselage, parts of the engine and various mechanical parts overnight, the defence ministry said.

Officials still have not announced the cause of the crash, but they have been anxious to end speculation that it might have been caused by a bomb planted on board, or a portable air defence missile.

A memorial on a pier outside Sochi, on December 26, 2016, as Russia observes a national day of mourning (Getty)

But some aviation experts have noted that the crew’s failure to communicate any technical problem, and the large area over which fragments of the plane were scattered, point to a possible explosion on board.

Russia’s main domestic security and counter-terrorism agency, the FSB, said there were “no indications or facts pointing at the possibility of a terror attack or an act of sabotage on board the plane.”

The FSB said that investigators are looking into bad fuel, pilot error, foreign objects stuck in the engines or equipment failure.