KYIV, Ukraine — The United Nations says more than 2 million people have fled Ukraine following Russia's invasion.
Data from the U.N. says most of the refugees have gone to Poland.
Other nearby countries, including Hungary, Moldova, Romania and Slovakia, are seeing thousands of refugees.
The U.N. has warned that the conflict could lead to the worst refugee crisis since World War II.
"As the situation continues to unfold, an estimated 4 million people may flee Ukraine," the U.N. said.
The mayor of Lviv, which is in western Ukraine, reportedly said his city is struggling to keep up with the influx of refugees.
On Tuesday, he asked for more support from the international community.