Vera and Nicole thought they had endured the worst of the war as Russia besieged their city, Mariupol, for weeks. The sisters helped neighbors bury neighbors, melted snow for drinking water, and survived a bombing that ripped a hole in the ceiling of their home.

But by mid-March, they knew it was time to go. They heard that Russian invaders were sweeping the southern port city and transferring Ukrainians by bus either to Russia or to territory under Russian control.

The sisters took Vera’s 4-year-old son, Kirill, escaped Mariupol on foot and embarked on a harrowing journey. They said they crossed a heavily mined road littered with corpses; encountered a Russian sniper near a church who waved them on; and survived an artillery barrage in a field of flowers. After two days, the trio staggered down a highway, only to be met by a Russian soldier who directed them to a crowded bus.

“He told us that he freed us and asked why our faces had turned black,” Nicole said. “The way forward may have been a prison – but it was our only option.”

The bus took them to a school in the nearby town of Nikolske, which they said had been turned into a Russian-run registration center where Ukrainians filled out forms with their personal information. It was their first contact with what Ukrainian and American officials and human rights groups have called “filtration” centers which they say are part of a system of forced evictions from Ukrainians to Russia.

Forced population transfers and so-called “filtration” were tactics used by Russia during the Chechen wars in the 1990s, according to Frederick W. Kagan, senior researcher and director of the Critical Threats Project at the American Enterprise Institute. He said the strategy was to terrify the population into submission, keep control over witnesses to atrocities, and separate anyone deemed resistant to a Russian takeover.

The story of Vera and Nicole, who asked that their surnames not be used for fear of Russian reprisals, first came to light when they contacted a British aid organisation, United with Ukraine, which has been working to bring aid to Mariupol since March. The group made contact with the New York Times.

The sisters, who said they were telling their story to show the world what was happening in Russian-held territory, also spoke to other media. They shared videos and a diary with The Times chronicling their life in Mariupol and part of their escape from the city, which is now almost entirely under Russian control.

Rachel Denber, Human Rights Watch’s deputy director for Europe and Central Asia, said the group had documented two witness accounts of being taken to filtration centers and said Russia’s actions ” bore all the hallmarks of a forcible transfer”. She added that the Fourth Geneva Convention, to which Russia is a signatory, prohibits the forcible transfer of civilians from occupied territories, which would make such forcible transfers a war crime.

“We can’t ignore the fact that there might be people who made an informed choice to go to Russia,” Denber said. But, she said, other Ukrainians are “leaving because they have no choice but to go to the occupying power or die.”

Roads outside Russian-controlled territory are also notoriously dangerous in places.

Ukraine’s UN Ambassador Sergiy Kyslytsya recently told the Security Council that there are filtration centers in three cities under Russian control – Nikolske, Manhush and Yalta. All three, like Mariupol, are part of the Donetsk region, which borders Russia.

Vera and Nicole said they briefly stayed in filtration centers in two of these three cities during their escape from Mariupol.

The two centers that Vera and Nicole passed through in Nikolske and Manhush were not heavily guarded and some were given the option of staying or leaving, they said. But they said it wasn’t really a choice: The Russians only offered safe passage in one direction, and that wasn’t into Ukrainian-held territory.

“For some, their homes were destroyed and there was nowhere to go,” Vera said. “Others were there to save their children. It was the only safe option they had left.

Tatyana Moskalkova, Russian commissioner for human rights, denied that Ukrainians were forcibly transferred to Russia. Russian President Vladimir Putin has said around 1 million Ukrainians have been taken to Russia, but he describes the move as evacuations.

Russian authorities have described the invasion of Ukraine as a necessary mission to help their ethnic relatives who they say have been discriminated against. They described efforts to bring displaced people from eastern Ukraine to Russia as a humanitarian operation aimed at rescuing them from Ukrainian authorities.

Vera and Nicole’s ordeal began around mid-March, when Russian soldiers were tightening their grip on Mariupol. Nicole said she heard a radio report saying the International Committee of the Red Cross had started evacuating people from the outskirts of town.

“We were terrified,” said Nicole, 21. “But each day we waited, we knew it was getting harder to leave.”

They decided to take the risk, even if it meant leaving members of their family behind.

They said goodbye to their brother, who feared that if he left with them, he would be arrested by Russian soldiers who allegedly strip searched men of military age, checking for proof of service or training, such as tattoos or calluses on their trigger. fingers. Their mother, separated from them since the start of the invasion, wouldn’t even know they were gone.

In a series of video calls over the past few weeks, the sisters described an escape punctuated by brushstrokes with death, including surviving artillery fire in a field.

“It was hell on earth,” said Vera, 27. “We were lying under fire, praying to survive.”

The Russian soldier they met on the highway put them on a bus to Nikolske. They were brought to a school that had been turned into a filtration site, they said. There was a long line of people filling out forms with personal information. Others slept on pieces of cardboard in the hallways.

They said they managed to escape deportation thanks to a mixture of ingenuity, luck and kindness from strangers.

They left Nikolske after a few hours with the help of a local Ukrainian bus driver recruited by the Russians to transport Mariupol residents to the filtration sites. He drove them to another school converted to an enrollment center in a nearby town, Manhush, where he suggested they would have better luck finding a ride to the Ukrainian town of Zaporizhzhia.

At the kindergarten, the sisters said there were hundreds of people waiting to be treated. They recorded their names, dates of birth and where they came from and slept one night in one of the classrooms with dozens of others.

They heard of a band of volunteers picking up people in vans and taking them to Ukrainian-held land. But Vera and Nicole were hesitant: they had heard that such roads were sometimes targeted by Russian forces.

Yet when a Ukrainian man walked into the school and offered them a free ride to Berdyansk, near the Russian border – one of the first towns seized by Russia during the war – the sisters took a chance. . Even though they would still be in Russian-held territory when they got there, they felt it best to keep moving forward. Moreover, they had a relative in Berdyansk.

“I don’t know what would have happened if this man hadn’t come into our lives at that time,” Nicole said.

From Berdyansk, the sisters boarded an evacuation van that was part of a humanitarian corridor to Zaporizhzhia in southeastern Ukraine. They knew they had reached Ukrainian-held territory when they saw bright yellow municipal buses on the roads.

“We stood in the street and started crying,” Vera said. “I never thought the sight of a bus could make me so happy.”