Nearly 5.4 million Ukrainians have fled their country since Russia invaded two months ago, the United Nations said Thursday, with more than 55,000 leaving in the past 24 hours.

In total, 5,372,854 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 55,635 over the figure given on Wednesday.

While the outflow has slowed significantly since March, UNHCR has projected that the conflict in Ukraine 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.

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:

- Poland -

Nearly six out of 10 Ukrainian refugees -- 2,968,716 so far -- have crossed into Poland, according to UNHCR numbers up to April 27.

Polish border guards put the number even higher, saying Thursday that three million people had crossed the border from Ukraine since the start of the invasion.

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

Meanwhile, more than 904,000 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.

- Romania -

A total of 801,453 Ukrainians have entered the EU member state as of April 27, 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. 

- Russia -

Another 641,752 refugees have sought shelter in Russia, according to data last updated on April 27.

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.

- Hungary -

A total of 507,849 Ukrainians had entered Hungary as of April 27.

- Moldova -

The Moldovan border is the closest to the major port city of Odessa. A total of 439,290 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.  

- Slovakia -

A total of 363,940 people had crossed Ukraine's shortest border into Slovakia as of April 27.

- Belarus -

Another 24,857 refugees made it north to Russia's close ally Belarus as of April 27.

- Returns -

At the same time, many Ukrainians have also travelled back into Ukraine. UNHCR said that between February 28 and April 26, Ukrainian border guards had registered 1,233,500 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."