Hundreds of Russian investigators are searching snow-covered fields near Moscow, where a Passenger Jet Crashed killing all 71 people on board.
Bad weather, human error or technical failure are seen as possible causes.
Officials do not see terrorism as a likely cause.
According to Russia's Investigative Committee, "when the plane crashed it was intact, there was no fire, and the explosion happened on impact".
Earlier some eyewitnesses had reported seeing the jet ablaze as it plummeted.
BBC News.