A Russian military official says there was was no explosion aboard a jet that crashed in the Black Sea en route to Syria but that terrorism has not been ruled out as a possible cause.
Authorities are trying to determine what caused the Defense Ministry Tu-154 aircraft to crash shortly after takeoff from the coastal city of Sochi on December 25, killing all 92 passengers and crew.
"There was no explosion on board, I can say that for certain," said Sergei Bainetov, the Russian Air Force flight safety chief who heads a commission investigating the crash.
"But an act of terror is not necessarily an explosion...It could have been any type of mechanical impact, so we are not discarding this version," Bainetov said.
The remark indicated that investigators haven't ruled out the possibility of a deliberate impact aimed at bringing the plane down.
Transport Minister Maksim Sokolov, however, repeated what he has said previously: that "a terror attack is not being considered as the main theory" of the cause of the crash.
Russia's top domestic security and counterterrorism agency, the Federal Security Service (FSB), said earlier in the week that investigators had found "no indications or facts pointing at the possibility of a terror attack or an act of sabotage."
The FSB said possible causes included bad fuel, pilot error, equipment failure, and objects stuck in the engines.
The crew of the plane, which had stopped in Sochi to refuel after flying from Moscow, did not report any problem to air-traffic controllers before the plane crashed less than 2 kilometers offshore.
More than 60 passengers were members of the military's Aleksandrov song-and-dance ensemble, also known as the Red Army Choir, which was to perform for Russian servicemen deployed in Syria to support President Bashar al-Assad's government in the war there. Nine Russian TV journalists and prominent charity worker Yelizaveta Glinka, or Doctor Liza, were also among the dead.