Human Rights Watch (HRW) says Russian and Russian-allied forces have been "forcibly transferring" Ukrainian civilians, including those fleeing fighting, to the Russian Federation or areas of Ukraine occupied by Russia.
The rights group said in a 71-page report, released on September 1, that the transfers are a "serious violation" of the laws of war that constitute war crimes and potential crimes against humanity.
"Ukrainian civilians should not be left with no choice but to go to Russia," said Belkis Wille, senior crisis and conflict researcher at HRW and co-author of the report, which also noted that thousands of Ukrainian citizens have been subjected to a form of compulsory, punitive, and abusive security screening called "filtration."
"No one should be forced to undergo an abusive screening process to reach safety," Wille added.
WATCH: 'You Are Russian Now': Ukrainian Family Recalls Deportation To Russia
Your browser doesn’t support HTML5
'You Are Russian Now': Ukrainian Family Recalls Deportation To Moscow
Russia launched its unprovoked invasion of Ukraine on February 24. Since then, it has taken control of large areas in the south while further deepening its footing in the east, where Russia-supported separatists have been fighting against Ukrainian troops since 2014.
Since the outbreak of the war, Russia has been accused of consistently committing war crimes for allegedly purposely shelling residential areas and civilian infrastructure such as hospitals, shopping malls, and cultural venues. There have also been several allegations of Russia of perpetrating torture, unlawful detentions, and forcible disappearances of civilians.
Moscow has denied all of the accusations.
HRW said it interviewed 54 people who went to Russia, went through filtration, had family members or friends who were transferred to Russia, or who supported Ukrainians trying to leave Russia.
Most had fled the southern port area of Mariupol, while several were transferred from the Kharkiv region.
SEE ALSO: Russia Filtration Centers Map Society In Ukraine's Occupied Regions Ahead Of 'Referendums'The group also interviewed dozens of civilians from the Mariupol area who were able to escape the war zone to Ukrainian-controlled territory without undergoing filtration.
The total number of Ukrainian civilians transferred to Russia remains unclear, but HRW said many were displaced and transported in "a manner and context that makes them illegal forcible transfers."
In late July, the state news agency TASS reported that over 2.8 million Ukrainians had entered Russia from Ukraine, including 448,000 children.
"Herding people further into Russian-occupied areas and onward to Russia without consent should immediately stop," Wille said.
"Russian authorities and international organizations should do everything they can to help those taken to Russia against their will who want to return home to be able to do so safely."