That figure accounts for almost a quarter of the country’s population, which was calculated at 44 million by the World Bank in 2020.
Of those who have left their homes, the majority – 6.48 million as of March 16, according to figures provided by the International Organization for Migration on Friday – have been internally displaced since the conflict began on February 24.
Others have sought refuge in neighboring countries, including Poland, Romania, Moldova, Hungary, Slovakia, Russia and Belarus.
“The war in Ukraine is so devastating that 10 million have fled – either displaced inside the country, or as refugees abroad,” he added.
UNHCR, the UN refugee agency, said on Thursday that more than 90% of the 3.1 million people who have left Ukraine are women and children.
Raouf Mazou, the UNHCR assistant commissioner, said this indicated a “heightened risk of gender-based violence and other forms of exploitation and abuse, including trafficking.”
UNICEF spokesman Joe English told CNN on Sunday that 1.5 million Ukrainian children have been made refugees by Russia’s invasion, and that a further 3.3 million children are currently displaced within the country.
“Each of these is an individual child whose life has been torn apart, whose world has been turned upside down,” English said.
Where have people fled to?
In the first three weeks of the conflict, two million people arrived in Poland from Ukraine, according to the UN, while more than a million went to other neighboring countries.
Mazou said last week that he estimated 490,000 Ukrainians had fled to Romania, 350,000 to Moldova, 280,000 to Hungary, and 228,000 to Slovakia.
Poland has become “one of the largest refugee hosting countries in the world” in the space of just a few weeks, Mazou added.
Grandi has previously called the sheer number of people fleeing their homes in Ukraine “terrifying,” and earlier this month described the situation as “the fastest growing refugee crisis in Europe since World War II.”
Ukrainian nationals can enter France without a visa, he said, adding that many of those arriving were only passing through on their way towards the large Ukrainian community in Spain.
Meanwhile, more than 187,000 refugees have arrived in Germany from Ukraine, the German Interior Ministry said on Thursday.
However, a ministry spokesperson said the actual number could be significantly higher due to the absence of border checks between Poland and Germany.
CNN’s Benjamin Brown, Joseph Ataman, Camille Knight and Amy Cassidy contributed to this report.