Massive search for bodies and black box under way after Syria-bound military jet carrying 92 crashed into Black Sea.

Russian rescuers have found the first parts of the Syria-bound military plane that plunged into the Black Sea, while officials have dismissed terrorism as a possible cause of the crash that killed all 92 people on board.

Investigators have yet to confirm the cause of the crash, but officials said on Monday that an act of terror was not being considered as a possible explanation, despite the plane and its black boxes still being underwater.

A spokeswoman for the Sochi-based search and rescue branch of the emergency ministry confirmed that parts of the plane had been found under water.

“The debris is at the depth of 27 metres one mile from shore,” Rimma Chernova, spokesperson, told AFP news agency.

‘Control mechanism’

The Russian military said that divers had retrieved “two elements of the plane’s control mechanism”.

Russia’s federal security service said it was looking into four suspected causes of the crash, which do not include terrorism.

“No signs or facts pointing to a possible act of terror have been received at this time,” Russia’s Federal Security Service said in a statement carried by national news agencies.

The probe is focusing on a pilot error, a technical fault, bad fuel and a foreign object in the engine as the four main scenarios, it added.

Vigils were held in Russia on Monday after Russian President Vladimir Putin declared a day of mourning.

More than 3,000 people are racing to find the remaining bodies and debris in a massive operation that includes 45 vessels, planes, helicopters and drones, along with divers and remotely-operated deepwater machines.

Transport Minister Maxim Sokolov said some of the bodies could have already been carried off by the “strong current” to Abkhazia, the separatist region of Georgia, and some of its own rescue workers have joined the search operation.

Along with the first 10 bodies, 86 body fragments were brought to the Russian capital for DNA analysis, defence ministry spokesman Igor Konashenkov said.

‘Black box’ recorders

The search party has not yet found the plane’s “black box” recorders, Emergency Situations Minister Vladimir Puchkov told Russian news agencies.

The Tu-154 jet, headed for Syria, went down on Sunday morning minutes after taking off at 5:25am local time (02:25 GMT) from Sochi’s airport.

The plane was taking Russia’s famed choir, the Alexandrov Ensemble, to a New Year’s concert at Hemeimeem airbase in Syria’s Latakia province.

READ MORE: Russia mourns plane crash victims

Mourners left flowers in front of the Moscow headquarters of the famed choir, more than 60 of whom were killed in the crash.

The defence ministry says the downed jet, a Soviet-era plane built in 1983, had last been serviced in September and undergone more major repairs in December 2014.

The last big TU-154 crash was in 2010 when a Polish jet carrying then-president Lech Kaczynski and much of Poland’s political elite went down in western Russia killing everyone on board.