More than five million people have fled Ukraine since the Russian invasion on February 24, UN figures showed on Friday.

UNHCR, the UN refugee agency, said 4,796,245 million Ukrainians had fled across the borders, while the UN's International Organization for Migration (IOM) says nearly 215,000 third-country nationals have also escaped to neighbouring countries.

The exodus is Europe's fastest-growing refugee crisis since World War II.

Friday's figures from the UNHCR were up 59,774 on those issued Thursday.

More than 2.7 million Ukrainian refugees -- nearly six in 10 who have left since the war began -- have fled to Poland. More than 725,000 reached Romania.

UNHCR figures show nearly 645,000 Ukrainians fled in February, with nearly 3.4 million doing so in March and more than 760,000 leaving so far this month.

Women and children account for 90 percent of those who have left Ukraine, with men aged 18 to 60 eligible for military call-up and unable to leave.

Nearly two-thirds of all Ukrainian children have been forced from their homes, including those still inside the country.

The nearly 215,000 third-country nationals who have fled across the borders -- people who are citizens of neither Ukraine nor the country they entered -- are largely students and migrant workers.

Beyond the refugees, the IOM estimates 7.1 million people have fled their homes but are still in Ukraine.

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.