U.S.-funded research has identified more than 210 sites where Ukrainian children have been taken for military training, drone manufacturing and other forced re-education by Russia, as part of a large-scale deportation program.

Yale's School of Public Health said in a report published on Tuesday that more than 150 new locations had been discovered since it published findings last year, when it alleged that Russian presidential aircraft had been used to transport children.

The latest research by Yale's Humanitarian Research Lab (HRL), based on open-source information and satellite imagery, said roughly half of the locations are managed by the Russian government.