The United Nations refugee agency (UNHCR) is expecting some 8.3 million people to flee Ukraine this year, revising up its previous projection.
More than 12.7 million people have fled their homes in the past two months, including 7.7 million people displaced internally and more than five million who have fled over borders, UNHCR spokeswoman Shabia Mantoo told a UN news briefing on Tuesday.
UNHCR had previously planned for some four million refugees in the immediate aftermath of Russia's invasion of Ukraine on February 24 but this was surpassed last month.
"The scale of the crisis, definitely the rapidity of people fleeing, we have not seen in recent times," Mantoo told the briefing.
Syria remains the biggest current refugee crisis in the world, with 6.8 million people having fled, she added.