A National Intelligence Council memorandum assesses that Russia with the help of proxy groups almost certainly is using so-called filtration operations to conduct the detention and forced deportation of Ukrainian civilians to Russia.
These operations have expanded during the course of the conflict to involve the screening of possibly thousands of individual Ukrainians. The filtration process includes temporary detention, data collection, interrogation, and in some cases abuse of detainees, and takes place in a variety of temporary processing centers—often in parallel with internally displaced persons (IDP) and refugee processing.
The NIC assesses that many individuals face one of three fates after undergoing filtration. Those who are deemed non-threatening may be issued documentation and permitted to remain in Russian-occupied areas of Ukraine, or in some cases forcefully deported to Russia. Others deemed less threatening, but still potentially resistant to Russian occupation, face forcible deportation to Russia and are subject to additional screening. Those deemed most threatening during the filtration process, particularly anyone with affiliation to the military or security services, probably are detained in prisons in eastern Ukraine and Russia, though little is known about their fates.