More than 5.4 million Ukrainians have fled their country since Russia invaded two months ago, the United Nations said, with tens of thousands joining their ranks every day.

In total, 5,429,739 Ukrainians have fled the country as refugees since February 24, according to the latest data from the UN refugee agency, UNHCR.

That marks an increase of 56,885 over the figure given on Thursday.

The UN is projecting that the war could produce 8.3 million refugees by the end of the year.

In addition to the Ukrainian refugees, the UN's International Organization for Migration (IOM) has said nearly a quarter of a million 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, meaning that more than 13 million people overall have been uprooted by the conflict.

The organisation appealed Friday for $514 million to help support eight million vulnerable people inside Ukraine, as well as two million of those who have fled abroad.

Almost two-thirds of Ukrainian children have fled their homes.

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 -- 2,992,575 so far -- have crossed into Poland, according to UNHCR numbers up to April 28.

Polish border guards put the number even higher, saying the influx from Ukraine passed the three-million-mark this week.

Many of them have travelled on to other states in Europe's Schengen open-borders zone.

Meanwhile, more than 924,000 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.

The UN projects that the war could produce 8.3 million refugees by the end of the year
The UN projects that the war could produce 8.3 million refugees by the end of the year AFP / Christophe ARCHAMBAULT

A total of 810,021 Ukrainians have entered the EU member state as of April 28, 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 656,381 refugees have sought shelter in Russia, according to data last updated on April 28.

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 513,848 Ukrainians had entered Hungary as of April 28.

The Moldovan border is the closest to the major port city of Odessa. A total of 441,437 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 367,904 people had crossed Ukraine's shortest border into Slovakia as of April 28.

Another 25,002 refugees made it north to Russia's close ally Belarus as of April 28.

At the same time, many Ukrainians have also travelled back to Ukraine. UNHCR said that between February 28 and April 28, Ukrainian border guards had registered 1,257,500 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".