Nearly 1 in 4 people in Ukraine forced out of their homes since Russia’s invasion

They include more than 3.3 million refugees who have poured into neighboring countries since Russia’s invasion on Feb. 24, according to the U.N. refugee agency.

Most have gone to Poland so far, though more than a million have escaped to other neighboring countries, such as Hungary and Slovakia, and including nearly 185,000 to Russia.

The U.N. children’s agency, UNICEF, says at least 1.5 million children have joined the outflow of refugees, facing risks it described as “real and growing.”

More than 500 unaccompanied children crossed from Ukraine into Romania in a period of three weeks, according to UNICEF, which warned that minors separated from their families were “especially vulnerable to trafficking and exploitation.”

Ukrainian refugees are flooding into Warsaw. Its mayor warns it’s on the brink.

Along Ukraine’s border, lines to get into Poland have stretched for miles, with people waiting through long days and frigid nights.

The exodus from Ukraine has become Europe’s fastest-growing refugee crisis since World War II. The European Union’s latest unprecedented measures will allow Ukrainians temporary protection anywhere in the 27-country bloc for up to three years — bypassing an asylum system that left others fleeing Africa and the Middle East in years-long limbo.

Local authorities and volunteers in Poland have organized reception centers for refugees. Many sleep on cots in open rooms. But officials in Polish cities like the capital, Warsaw, are appealing for help as they warn the centers are nearing or at capacity, with housing running thin.

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Inside the country, thousands of Ukrainians have evacuated from their battered or besieged cities to other parts of Ukraine through “humanitarian corridors” agreed upon by Kyiv and Moscow during temporary cease-fires.

Among those shuttled away from the front lines in recent days were residents of the southern port of Mariupol, where a bloody onslaught has descended into street fighting. They recounted being trapped in basements with little to eat and no electricity or water as the casualty toll mounted.

The U.N. human rights office in Ukraine said it has recorded more than 900 civilian deaths, including 75 children, and 1,459 injured. Still, the agency said it believes that the “actual toll is much higher.”

Hannah Knowles contributed to this report.