ZAHONY, Hungary — After bombs started falling in her hometown of Kharkiv, Annamaria Maslovska left her friends, her toys, and her life in Ukraine and set off on a days-long journey with her mother toward safety in the West.

After finally crossing the Hungarian border by train along with hundreds of other Ukrainian refugees, the 10-year-old Maslovska said she had begun to worry about her friends in Kharkiv after the messages she sent to them on Viber went unanswered.

“I really miss them because I can’t contact them, they just read my messages and that’s all. I really worry, because I don’t know where they are,” she said in clear English from inside the train station at the border town of Zahony.

Annamaria, who was raised alone by her mother, is one of more than 1 million children who have fled Ukraine in the less than two weeks since Russia first invaded the country, something UNICEF spokesperson James Elder called “a dark historical first.”

That means that children represent around half of the more than 2 million people that have fled the war, an exodus that the U.N. refugee agency has called the fastest-growing refugee crisis in Europe since World War II.

Most of those fleeing the war have entered countries on Ukraine’s western border, like Hungary, Poland, Slovakia, Romania and Moldova. The majority have gone into Poland, where 1.33 million refugees have crossed according to the Polish Border Guard agency.

Moldova Prime Minister Natalia Gavrilița told CNN on Sunday that one in every eight children in her country is a refugee.

Valeria Varenko, 9, fled with her mother Julia and her little brother from Ukrainian capital Kyiv after bombings had forced them to shelter in the basement of their apartment building.

After driving day and night for two days, the family reached a temporary refugee reception center in Barabas, Hungary. Valeria said she wanted to tell children left behind in Ukraine to be careful, and not to touch any objects in the street because “they could be bombs which can hurt them very much.”

Her father stayed behind to help defend Kyiv from Russian troops edging closer to the city. She said she was very proud of him, and that she misses him “very much.”

“I would really like him to come, but unfortunately he isn’t allowed,” she said.

Her mother Julia, 30, said that even though she was afraid herself, she’d told Valeria to be strong and brave, and that the most important thing was keeping their family together.

“We will pray that this will all be over soon so we can come home,” Julia said.

In addition to children, most other refugees are women — the mothers and grandmothers of the children that are bringing them to safety — since Ukrainian men from age 18 to 60 aren’t permitted to leave the country.

That policy is aimed at keeping men available to fight against Russian forces that are making deeper incursions into Ukrainian territory.

Annamaria’s hometown of Kharkiv, Ukraine’s second-largest city with 1.5 million inhabitants, has undergone heavy bombardment by Russian forces. Residential areas in the city near the Russian border were shelled for several days before a missile strike hit a government building in the city’s central Freedom Square last week, killing at least six.

Ukrainian President Volodymyr Zelenskyy called the attack “frank, undisguised terror.”

Even though she’s only 10, the precocious Annamaria, now a refugee, already knows she wants to be an actress in the United States, and is proud of speaking English at a high level.

“I want to be an actress in USA and English is a very popular language,” she said. “A big percent of people in the world know it and it’s very easy to speak it in other countries.”

She and her mother, Viktoria, planned to travel on to Hungary’s capital, Budapest, but didn’t know where they would go after that. Annamaria said she hoped to visit Disneyland in Paris.

Once the war ends, she said, she wants to go back to Kharkiv and reconnect with her friends who have been scattered by Russia’s violent invasion.

“If war stops, I really want to go home because there are my friends, there are beautiful parks, supermarkets, centers, and playgrounds behind my house,” she said. “Kharkiv, it’s like a piece of your heart.”