Russia has established filtration camps in the embattled town of Vovchansk, Kharkiv Oblast Governor, Oleh Syniehubov, said on June 4.
Speaking to national TV, Syniehubov said that although "few people remain" in the part of the town occupied by Russian forces, those that do "are used by the enemy as human shields."
"And, according to our information, filtration camps have been set up there," he added.
Filtration camps are used by Russian forces to identify and document Ukrainians in occupied territories.
Those who pass through them are often subject to torture, sexual violence and other violations, sometimes before being forcibly deported to Russia.
Russia launched a new offensive on May 10 in northern Kharkiv Oblast and Vovchansk became the scene of some of the heaviest fighting.
As of May 30, Russian forces continued to control a handful of settlements on two separate axes, one near the town of Vovchansk and the other towards the village of Lyptsi, where they have advanced a maximum of just 10 kilometers from the state border.
Ukrainian forces control about 70% of the town as of May 31, Nazar Voloshyn, the spokesperson of the Khortytsia group of forces, told Hromadske Radio.
Vovchansk is described by Ukrainian officials as almost destroyed, while Russia keeps attacking other neighboring settlements, inflicting civilian casualties.