KYIV, Ukraine (AP) — Ukraine's prosecutor-general says it's investigating the forced transfer of Ukrainian children to Belarus, adding to allegations that Russia is also transferring them to its territory.

Ukrainian law enforcement officers said they are investigating the relocations from the Russian-occupied Donetsk, Luhansk, Zaporizhzhia, Kherson and Kharkiv regions to Belarus.

Pavel Latushka, a former Belarusian minister of culture now in exile in Poland, heads an opposition group, the National Anti-Crisis Management, which has been documenting the deportations. Latushka and his team turn evidence over to international organizations, hoping that the International Criminal Court will issue an arrest warrant for Belarusian President Alexander Lukashenko, as it did for Russian President Vladimir Putin.

In March, the ICC issued arrest warrants for both Putin and his commissioner for children’s rights. Judges in The Hague said they found “reasonable grounds to believe” that the two were responsible for war crimes, in particular for the illegal deportation and transfer of children from the occupied regions of Ukraine to Russia.

Belarusian authorities have said that Belarus will take in more than 1,000 children aged 6 to 15 from the partially occupied Donbas in eastern Ukraine for “recovery.”

Belarusian opposition leaders say more than 2,150 Ukrainian children, including orphans aged 6 to 15, were sent to so-called health camps and sanatoriums in Belarus.

Earlier this week, Latushka urged the European Union to keep sanctions against a Belarusian state fertilizer producer, Belaruskali. He accuses the company of financing the forced transfers of the children. The sanctions apply to Belaruskali, one of the world’s largest exporters of potash fertilizers, and the Belarusian Potash Company, which exports Belaruskali’s products.

“Belaruskali is the firm that finances the deportation of Ukrainian children,” Latushka, who was sentenced to 18 years of prison in absentia in March by a court in Belarus, told The Associated Press.

His group alleges that the Ukrainian orphans deported to Belarus undergo a process of Russification before they're sent to Russia for adoption, something they say amounts to violations of the Geneva conventions against war crimes.

Lukashenko’s government denies those claims.