The places identified in the report include, among other things, summer camps, cadet schools, care facilities and a military base. More than half of the places are managed by federal or local authorities, according to public data.
At nearly two-thirds of the identified places, there have been attempts to "re-educate" the children to share Russia's worldview, and in at least 39 places, what is described as military training and indoctrination has been ongoing, the investigation shows.
The Russian system is described in the report as "potentially unparalleled for large-scale re-education, military training and boarding accommodation that can accommodate tens of thousands of children from Ukraine for long periods".
Ukraine has accused Russia of having taken away up to 20,000 children from parts of eastern and southern Ukraine since Russia launched its full-scale invasion in February 2022. It has been described by Western assessors as a clear Russian strategy in the war.