Maria Lvova-Belova, Russian ombudswoman for children’s rights, wanted by the International Criminal Court (ICC) in Hague, has reported that since the beginning of the full-scale invasion of Ukraine, the Russians have deported more than 700,000 Ukrainian children to Russia.
At least in Ukraine if you’re under 18 you’re considered to be a child.
This, plus children from the areas that were occupied by russia previously (Kherson region, Kharkiv region, possibly even to the north of Kyiv)