Speed sensors that were iced over may have caused a passenger jet to crash near Moscow, killing all 71 people on board, investigators say.
The faulty instruments could have indicated wrong speed data, Russia’s Interstate Aviation Committee said.
The Saratov Airlines jet went down minutes after take-off from Moscow’s Domodedovo airport on Sunday.
No emergency call came from the plane. The Antonov An-148 was en route to Orsk in the Ural mountains.
More than 700 people are involved in the search operation, struggling through deep snow.
The emergencies ministry is collecting DNA samples from victims’ relatives in order to identify the victims.
What do we know so far?
Contact was lost minutes after the plane took off at 14:27 (11:27 GMT) on Sunday.
Flight-tracking site Flightradar24 said it then descended at the rate of 1,000m (3,300ft) per minute.
The jet, which was reportedly seven years old, was being flown by an experienced pilot who had 5,000 hours of flying time, the airline told Ria-Novosti news agency.