Russia has “systematically relocated” possibly more than 6,000 children from Ukraine to several re-educating and adoption facilities in occupied Crimea and mainland Russia, which could be considered a war crime, the Yale School of Public Health’s Humanitarian Research Lab (HRL) warned.

Moscow authorities launched a criminal investigation on Thursday, after 29 school children with food poisoning symptoms have been hospitalized, the Moscow Interregional Investigative Directorate said in astatement.