Senior US administration officials have warned of a heavy death toll should Russia decide on a full-scale invasion of Ukraine, the New York Times reported on Saturday. Senior officials told US lawmakers this week that a large-scale Russian invasion could kill as many as 50,000 civilians and prompt a refugee crisis in Europe, according to the report. They warned of “enormous possible human costs” if Russian President Vladimir Putin were to go ahead with a full invasion, including the potential deaths of 25,000 to 50,000 civilians, 5,000 to 25,000 members of the Ukrainian military and 3,000 to 1…