"I'm shocked with the airline accident in Sheremetyevo airport which takes a heavy toll. We're grieving over victims along with their families", wrote PM Pavel Filip on his Twitter.
Forty-one people died after a Russian plane made an emergency landing and burst into flames just after takeoff from Moscow's Sheremetyevo airport.
Two children are among the dead. The jet had 73 passengers and five crew.
"There are 37 survivors - 33 passengers and four members of the crew," said Yelena Markovskaya, an official involved in the investigation of the crash.