As Russian forces laid siege to the Ukrainian city of Mariupol last spring, children fled bombed-out group homes and boarding schools. Separated from their families, they followed neighbors or strangers heading west, seeking the relative safety of central Ukraine.

Instead, at checkpoints around the city, pro-Russia forces intercepted them, according to interviews with the children, witnesses and family members. Authorities put them on buses headed deeper into Russian-held territory.

“I didn’t want to go,” said Anya, 14, who escaped a home for tuberculosis patients in Mariupol and is now with a foster family near Moscow. “But nobody asked me.”

In the rush to flee, she said, she left behind a sketchbook containing her mother’s phone number. All she could remember were the first three digits.

Since Russia’s invasion of Ukraine began in late February, Russian authorities have announced with patriotic fanfare the transfer of thousands of Ukrainian children to Russia to be adopted and become citizens. On state-run television, officials offer teddy bears to new arrivals, who are portrayed as abandoned children being rescued from war.

In fact, this mass transfer of children is a potential war crime, regardless of whether they were orphans. And although many of the children did come from orphanages and group homes, authorities also took children whose relatives or guardians want them back, according to interviews with children and families on both sides of the border.

As Russian troops pushed into Ukraine, children like Anya who were fleeing newly occupied territories were swept up. Some were taken after their parents had been killed or imprisoned by Russian troops, according to local Ukrainian officials.

This systematic resettlement is part of a broader strategy by Russian President Vladimir Putin to treat Ukraine as a part of Russia and cast his illegal invasion as a noble cause. His government has used children — including the sick, poor and orphaned — as part of a propaganda campaign presenting Russia as a charitable savior.

Through interviews with parents, officials, doctors and children in Ukraine and Russia, The New York Times identified several children who had been taken away. Some returned home. Others, including Anya, remain in Russia.

The Times interviewed Anya several times through instant messages, exchanged voice memos with her and verified key details through her friends, photographs and a journal she kept identifying other children she had been with. She asked reporters not to contact her foster parents, who had told her not to talk to outsiders.

Anya had lived apart from her mother and was in only sporadic contact with her before the war. Without the phone number, Anya said she could not reach her.

At first, reporters could not, either.

The Times is not identifying Anya’s full name. A shy girl with a passion for drawing, she said that her Russian foster family treated her well but that she ached to return to Ukraine. Soon, though, she said she would become a Russian citizen. “I don’t want to,” she said. “My friends and family aren’t here.”

Anya and others described a wrenching process of coercion, deception and force as children were shipped to Russia from Ukraine. Together, their accounts add to a growing body of evidence from governments and news reports about a removal-and-adoption policy that targets the most vulnerable children in the most dangerous situations.

Transferring people out of an occupied territory can be a war crime, and experts say the practice is especially thorny when it involves children, who may not be able to consent. Ukrainian officials accuse Russia of perpetrating a genocide. The forced transfer of children, when intended to destroy a national group, is an act of genocide under international law.

Russian officials have made clear that their goal is to replace any childhood attachment to home with a love for Russia.

Russia’s commissioner for children’s rights, Maria Lvova-Belova, has organized the transfers and said that she herself adopted a teenager from Mariupol. Lvova-Belova, who is under Western sanctions, said the boy had been homesick at first and even attended a demonstration supporting Ukraine.

“He was yearning for the house in which he grew up, friends and his dear Mariupol,” she wrote on Telegram. But the children soon come to appreciate their new home, she said.

The exact number of resettled children is not clear. Russian authorities did not respond to questions from the Times. Ukrainian authorities said they did not have an accurate count, but placed the figure in the thousands.

In April, Russian authorities announced that more than 2,000 children had arrived in Russia. Most came from group homes and orphanages in territory long occupied by Russia. Russian officials said that 100 had come from recently occupied areas. In the following months, they announced hundreds of new arrivals.

While the resettlement of children from newly occupied lands has so far been sporadic, the Russian government recently announced plans to resettle these children more efficiently, raising the prospect of many more transfers.

Russia’s wartime tactic exploits some of the thorniest and most intimate family dynamics. Russian families spoke of adoption as a matter of patriotism, but they also expressed a heartfelt desire to provide a better life for the children. And while many Ukrainian parents try to recover their children, others do not, whether for financial reasons or because their relationships were severed even before the war.

In the Siberian city of Salekhard, along the Arctic Circle, Olga Druzhinina said she adopted four children, ages 6-17, from around the Ukrainian city of Donetsk, more than 1,600 miles away. Russia recently illegally annexed the Donetsk region and three others in eastern and southern Ukraine.

“Our family is like a small Russia,” Druzhinina said in an interview. “Russia took in four territories, and the Druzhinin family took in four children.”

She said she was awaiting a fifth child and considered the children fully Russian. “We are not taking what is not ours,” she said.

‘They Simply Took Away All the Children’

Anya was living and recovering from tuberculosis in a group home on a wooded campus with a red swing set. As explosions blew out the building’s windows and doors, the children fled to the basement. Anya read fairy tales to the youngest ones and passed the time by drawing.

Children in government homes are often labeled orphans, but most do have families. Ukraine makes it easy for parents struggling with illness, substance abuse or financial hardships to place their children — temporarily or permanently — in state-run institutions. The United Nations estimated that about 90,000 children were in such homes across Ukraine before the war.

Many parents rescued their children from Anya’s building. Others did not, whether because they could not make their way through the war zone or, like Anya’s mother, they were unreachable.

A Ukrainian volunteer crammed Anya and the 20 or so remaining children into an ambulance bound for the city of Zaporizhzhia, other children recalled. But they were rerouted at a Russian checkpoint, they said, and ended up with dozens of children at a hospital in the city of Donetsk, the capital of a region that Russia has occupied since 2014.

This region is the heart of Russia’s removal-and-adoption policy. Since the invasion began, Putin’s government has promoted the systematic transfer of children from the area’s orphanages and group homes.

For Anya and others taken from newly occupied territories in Ukraine, Donetsk also served as a sort of way station en route to Moscow.

Ivan Matkovsky, 16, said he, too, ended up in a Donetsk hospital after fleeing a government boarding school in Mariupol and being rerouted at a Russian checkpoint.

Among the other children in the hospital, Ivan said, was an 8-year-old boy named Nazar, who had hidden with his mother in a Mariupol theater that was pummeled by airstrikes in one of the war’s defining atrocities. He survived but never found his mother.

Local authorities around Mariupol told similar stories of children who survived the Russian assault and ended up at nearby hospitals. One toddler arrived in a stroller along with a handwritten note that read, “This is Misha. Please help him!” said Vasyl Mitko, an official in the town of Nikolske who helped at the hospital.

But one by one, Mitko said, the children vanished. “They simply took away all the children who were left without parents,” he said. “We still do not know where these children are.”

‘We Will Show You Moscow’

Ukrainian parents who managed to locate their children in Donetsk, gather the right paperwork and contact the right people had a chance at reunification. But even then, children and parents say, the authorities pressured children to go to Russia voluntarily.

“They were promised a new, wonderful life,” said Natalia, a foster mother from Mariupol. Her 15-year-old foster son agreed to go to Russia, she said. She asked not to be identified by her full name because she worried it would make it harder to get him back. “These are children of a difficult fate,” she said. “They are easily deceived.”

Timofey Chmel, 17, who was in the Donetsk hospital with Anya, said authorities promised lives of leisure and love in Moscow.

“We were told: ‘If you need gadgets or clothes, just tell us. We will buy everything. If you want, you can just go and relax. We will show you Moscow,’” he said. “‘If your parents abandoned you, they do not need you. We will help you.’”

Timofey refused and was later reunited with his foster mother. Ivan, the 16-year-old boarding school student, said he and one of his schoolmates managed to contact their school’s headmaster, their legal guardian, and arrange their return.

When children had nobody to call, or when parents were unable or unwilling to brave the journey to Donetsk, the children were given no choice.

While Ivan was waiting for the headmaster to pick him up, he said, the other children were put on a bus for Russia. They protested. “No one listened to them,” Ivan said. “They had no choice.”

Ivan is still in contact with three of the children in Russia. He does not know what became of Nazar, the boy who survived the theater attack.

Anya, too, had no choice. She said a doctor told her that she would rest in an institution in the Moscow region for three weeks. That was months ago.

“I was just told,” she said. “And that was it.”

‘Our Little Fellow Citizens’

The Russian government carefully choreographs the pipeline from the Donetsk region to Moscow.

“Now you are at home, in a circle of friends,” the Russia-imposed mayor of Donetsk told a group of boys from Mariupol. He shared a video of the moment on Telegram.

Russian officials in Donetsk invite reporters into group homes to witness children receiving cellphones, gifts and clothes. State-run television airs the children’s arrival in Moscow by train.

Putin instituted a streamlined process in May allowing the swift nationalization of Ukrainian children. The first group became Russian citizens in July, officials announced.

“I did not recognize those kids with whom we traveled in April on the train to their new life,” Ksenia Mishonova, the children’s rights commissioner for the Moscow region, said in a statement. “Now they are our little fellow citizens!”

Some children were indeed orphaned or abandoned in Ukraine and prefer their lives in Russia. The Times spoke to one teenager from Mariupol who said he had no family back home. He said his foster family loved him like he was their own.

Others, like Anya, long to return.

She participated in a weekly class called Conversations About Important Things. The half-hour lesson, introduced recently by Putin, teaches children to be proud of Russia.

Sometimes, Anya said, she cries, wondering if something horrible has happened to her family.

After more than a month of reporting, Times reporters reached Anya’s mother, Oksana, in Ukraine. With no job, no internet access, a small disability pension and a war going on, she said she had no idea how to find her daughter.

“I’m looking everywhere, but I can’t find her,” she said. “She is looking for me.”

She said she did not know that Anya had been taken to Russia.

Reporters told Anya and Oksana how to contact each other. The prospect of Anya returning home, though, is unclear. Ukrainian officials have been tight-lipped about how they have gotten dozens of children back from Russia.

“Is this really her number?” Anya asked.

This article originally appeared in The New York Times.