More than 5 million people have fled Ukraine in the nearly two months since Russia's full-fledged invasion began, according to a tracker from the United Nations High Commissioner for Refugees.

Filippo Grandi, the U.N. refugee commissioner, confirmed the milestone on Twitter.

"They have left behind their homes and families. Many would do anything, and some even risk going back, to see their loved ones," he wrote. "But every new attack shatters their hopes. Only an end to the war can pave the way for rebuilding their lives."

The U.N. agency had initially estimated that 4 million Ukrainians would flee the conflict — a number that was exceeded at the end of March, just over a month after Russia first invaded.

Overall, more than 10 million Ukrainians have so far been displaced by the war.

Krish O'Mara Vignarajah, president of Lutheran Immigration and Refugee Service, told The Hill that 5 million refugees represents 11% of Ukraine's population, meaning nearly 1 in 8 people have fled the country.

"Reaching 5 million refugees is a grim milestone of the toll Putin's aggression has taken on civilians," she wrote on Twitter. "With each day that passes, people who escape are even more vulnerable, having lived through months of conflict with no end in sight."

The vast majority of those who have fled the country — nearly 3 million — have gone to Poland, followed by other Eastern European countries like Romania and Hungary.

Some have made it to the U.S., including by traveling to Mexico's northern border and asking agents for admission on humanitarian grounds. The Biden administration has said the U.S. will accept up to 100,000 Ukrainian refugees, and is also granting temporary protection from deportation to thousands of Ukrainians already in the U.S.

Meanwhile, some refugees are already traveling back to Ukraine, despite warnings from officials that it's not yet safe to return. The Polish border service reported over the weekend that more people had crossed the border to Ukraine than fled into Poland for the first time since the war began.

This story originally appeared in the Morning Edition live blog.

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