Here's another older source: https://www.independent.co.uk/news/world/europe/trump-ukraine-children-russia-war-kidnapping-evidence-b2717730.html
Children from Eastern Europe have been considered prime trafficking victims for several decades now. They are usually white and easily accessible, often sitting out on the streets.
Here's a documentary about Romanian street children: https://youtu.be/HDiIrdzFGCY
Here's Robert Maxwell trafficking them: https://www.nli.org.il/he/images/%20nnl_archive_al990040300950205171/NLI#$FL45875197
There is substantial evidence that torture, snuff, rape, bestiality, and CSAM materials coming from Russia are made by Putin's request and put out by his request to accrue blackmail on the people who view them online. A large part of what many world leaders want today are just straight up children and babies as a commodity.