People from Mariupol and nearby towns step out a bus, with a sign on the window that reads in Russian: Children , and arrive at a refugee center fleeing from the war, in Zaporizhzhia, Ukraine, Thursday, April 21, 2022. Mariupol. AP
In total, 5,264,767 people have fled Ukraine as refugees since February 24, according to the latest data from the UN refugee agency, UNHCR.
That marks an increase of 32,753 over Monday's figure.
While the outflow has slowed significantly since March, UNHCR said Tuesday it now projects that three million more Ukrainians could become refugees by the end of the year.
UNHCR spokeswoman Shabia Mantoo said the new projection of 8.3 million Ukrainian refugees was a planning figure, and that it was unclear when it would be reached amid a "highly dynamic" situation.
"This displacement has been on such an expansive scale, and the rapidity of this we haven't seen in recent times," she told reporters in Geneva.
The UN's International Organization for Migration (IOM) said an additional 224,975 citizens of third countries -- largely students and migrant workers -- have also escaped to neighbouring countries since the invasion began.
Women and children account for 90 percent of those who have fled abroad, with men aged 18 to 60 eligible for military call-up unable to leave.
Beyond the refugees, the IOM estimates more than 7.7 million people have been displaced within Ukraine.
Almost two-thirds of Ukrainian children have had to flee their homes, including those who remain in the country.
Before the invasion, Ukraine had a population of 37 million in the regions under government control, excluding Russia-annexed Crimea and the pro-Russian separatist-controlled regions in the east.
Here is a breakdown of how many Ukrainian refugees have fled to neighbouring countries, according to UNHCR:
Nearly six out of 10 Ukrainian refugees -- 2,922,978 so far -- have crossed into Poland, according to UNHCR numbers up to April 25.
Many of them have travelled on to other states in Europe's Schengen open-borders zone.
Meanwhile, more than 800,000 people have crossed from Poland into Ukraine, Polish border guards said.
Before the war, Poland was home to around 1.5 million Ukrainians, chiefly migrant workers.
A total of 782,598 Ukrainians have entered the EU member state as of April 25, including a large number who crossed over from Moldova, wedged between Romania and Ukraine.
The vast majority are thought to have gone on to other countries.
Another 614,318 refugees have sought shelter in Russia, according to data last updated on April 25.
In addition, 105,000 people crossed into Russia from the separatist-held pro-Russian regions of Donetsk and Lugansk in eastern Ukraine between February 18 and 23.
A total of 496,914 Ukrainians had entered Hungary as of April 25.
The Moldovan border is the closest to the major port city of Odessa. A total of 435,275 Ukrainians have crossed into the non-EU state, one of the poorest in Europe, with a population of 2.6 million. Most have moved on.
A total of 357,560 people had crossed Ukraine's shortest border into Slovakia as of April 25.
Another 24,578 refugees made it north to Russia's close ally Belarus as of April 24.
At the same time, many Ukrainians have also travelled back into Ukraine. UNHCR said that between February 28 and April 25, Ukrainian border guards had registered 1,185,500 Ukrainians returning to the country.
UNHCR stressed though that "this figure reflects cross-border movements, which can be pendular, and does not necessarily indicate sustainable returns as the situation across Ukraine remains highly volatile and unpredictable.