Nearly five million Ukrainians have fled the war since Russia invaded the country, alarming the situation and voicing concern that the situation may worsen, the United Nations said Tuesday.
UNHCR, the UN refugee agency, said 4,980,589 Ukrainians left since Russia invaded on February 24 - a figure up 46,174 on Monday's total.
Nearly 215,000 third-country nationals - mostly students and migrant workers - have escaped to neighbouring countries, so around 5.2 million people have fled Ukraine since the war began, according to the UN's International Organization for Migration IOM.
Since World War II, officials say it's the fastest-growing refugee crisis in Europe.
UNHCR spokeswoman Shabia Mantoo told reporters in Geneva that the borders remain open, people can access safety and when they get to the neighbouring countries they have access to assistance.
On Tuesday, Russia's defence minister said Moscow was trying to liberate east Ukraine, and the ministry said Moscow launched dozens of air strikes across eastern Ukraine overnight.
Kyiv accuses Russian forces of unleashing a new offensive in the Donbas region.
We're watching with concern to see what will happen, but it's alarming that we are approaching five million refugees from Ukraine within the space of a few weeks, said Mantoo.
Women and children account for 90 percent of those who fled, with men aged 18 to 60 eligible for military call-up and unable to leave.
Nearly two-thirds of Ukrainian children have been forced out of their homes, including those still inside the country.
More than 2.8 million Ukrainian refugees have fled to Poland. Three quarters of a million people have reached Romania.
Nearly 645,000 Ukrainians fled in February, with nearly 3.4 million doing so in March and 945,000 leaving this month, according to UNHCR figures.
The IOM estimates that 7.1 million people are displaced within 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.
According to UNHCR: Here is a breakdown of how many Ukrainian refugees have fled to neighbouring countries.
Nearly six out of 10 Ukrainian refugees -- 2,800, 713 -- have so far crossed into Poland.
Many of them have travelled to other states in the Schengen open-borders zone.
738,000 people have crossed into Ukraine from Poland, Polish border guards said.
Before the war, Poland was home to around 1.5 million Ukrainians, chiefly migrant workers.
A total of 750,693 Ukrainians entered the EU member state, including a large number who crossed over from Moldova, wedged between Romania and Ukraine.
The vast majority of people are thought to have gone on to other countries.
Another 535,842 refugees have sought refuge in Russia.
Between February 18 and 23, 105,000 people crossed into Russia from the separatist-held pro-Russian regions of Lugansk and Donetsk in eastern Ukraine.
The Moldovan border is the closest to the major port city of Odessa. A total of 425,227 Ukrainians have crossed into the non-EU state, one of the poorest in Europe.
Most of the people who entered the former Soviet republic of 2.6 million people have moved on.
More than 23,609 refugees have made it north to Russia's close ally, Belarus.