Just over 2 million Ukrainians have fled their country since Russia began its attack 12 days ago, NPR reports Tuesday per a United Nations tracker.
Of the 2 million refugees, at least half are children, reports UNICEF. The 2 million total represents about 4 to 4.5 percent of Ukraine's population, notes NPR and Politico.
The number of Ukrainian refugees has "increased exponentially" in recent days, NPR writes; as recently as Wednesday, roughly one week after the invasion began, the total count topped 1 million.