Since the Russian invasion began on February 24 more than five million people have now fled Ukraine, the United Nations refugee agency said.
The Geneva-based UN High Commissioner for Refugees, UNHCR, on Wednesday put the total number of refugees at 5.01 million.
More than half of the total, over 2.8 million, fled at least at first to Poland.
Although many have stayed there, an unknown number have travelled onward.
There are few border checks within the European Union.
The UNHCR said on March 30 that four million people had fled Ukraine.
The exodus was somewhat slower in recent weeks than at the beginning of the war.
In addition to the refugees, the UN says that more than seven million people have been displaced within Ukraine.
Ukraine had a pre-war population of 44 million.