Ukrainian children have been taken to at least 210 facilities in Russia and areas of Ukraine that are under Moscow’s control as part of a Kremlin attempt to ensure their loyalty to President Putin, a report has said.

The facilities stretch across 3,500 miles, from the Black Sea to Siberia and the coast of the Pacific Ocean, according to research by Yale University’s Humanitarian Research Lab (HRL).

It accused Moscow of operating a “potentially unprecedented” system of “re-education” and forced military training for Ukrainian children. Children also produce drones and other military equipment for Russia’s army, the report said. Ukraine says Russia has abducted around 20,000 of its children since the start of the Kremlin’s full-scale invasion in 2022.

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The facilities include military cadet schools, a military base, medical facilities, a religious site, secondary schools and universities, a hotel, family support centres and orphanages, and most frequently, camps and sanatorium, HRL said. It cited open-source information and satellite imagery. Russia’s government directly manages more than half of the facilities, according to the report.

HRL said the facilities were part of Moscow’s wider attempt to “Russify” the residents of Ukrainian territories that are under the control of the Kremlin’s forces.

“[Russia] explicitly targets children, especially those in vulnerable categories such as orphans and those living close to the front line,” it said. Russia’s treatment of Ukrainian children was “likely to leave generational scars”, it said.

Re-education programmes involving “cultural, patriotic or military programming that aligns with pro-Russia narratives” have taken place at 130 of the sites, while almost 40 facilities, including specially built “Warrior” training camps, have been used for the “militarisation” of Ukrainian children, HRL said.

Children are reported to have taken part in shooting and grenade-throwing competitions, and received firearms, drone and tactics training. The report could not say whether any of the children who had received Russian military training had been deployed to fight against Ukrainian forces.

The children ended up in Russia or Russian-occupied territory through a variety of routes, HRL said. Some were forcibly taken from their parents by Kremlin-loyal officials or troops during the early months of the war, while others were removed from Ukrainian state care homes.

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Others were sent by their parents to Russian-run summer camps that were only supposed to last a few weeks. Some have since been sent back to Ukraine “after undergoing re-education”.

Putin and Maria Lvova-Belova, the Kremlin’s top official for children’s rights, have been charged by the International Criminal Court with the mass abduction of Ukrainian children. Kyiv says Moscow is trying to erase the children’s Ukrainian identity and that it will insist on their return in any eventual ceasefire or peace deal with Russia. Moscow denies kidnapping children and says they were “rescued” by Russian troops from war-zones after Putin sent tanks into Ukraine.