The U.N. migration agency said Friday that nearly 6.5 million people have been displaced inside Ukraine, on top of the 3.2 million who have already fled the country.
That means that around a quarter of Ukraine's 44 million people have been forced from their homes.
The estimates from the International Organization for Migration suggests Ukraine is fast on course in just three weeks toward the levels of displacement from Syria's devastating war, which has driven about 13 million people from their homes both in the country and abroad.
The findings come in a paper issued Friday by the U.N. Office for the Coordination of Humanitarian Affairs.
The projections also found that "over 12 million people are estimated to be stranded in affected areas or unable to leave due to heightened security risks, destruction of bridges and roads, as well as lack of resources or information on where to find safety and accommodation."
The paper cited the IOM figures as "a good representation of the scale of internal displacement in Ukraine — calculated to stand at 6.48 million internally displaced persons in Ukraine as of March 16."
UNHCR, the U.N. refugee agency, has said fighting that has followed Russia's invasion of Ukraine on Feb. 24 has sparked Europe's gravest refugee crisis since World War II.
"By these estimates, roughly half the country is either internally displaced, stranded in affected areas or unable to leave, or has already fled to neighboring countries," he said, alluding to Ukraine's population of about 44 million before the war began.
The paper said that 9.56 million people have been displaced by the war so far, as of Wednesday, and another 2.2 million people were considering leaving. IOM estimates that more than 3 million people had fled abroad as of Wednesday.
UNHCR, in its latest figures released Friday, said more than 3.2 million people have fled Ukraine.
Additional reporting by The Associated Press.