Russia has taken DNA samples from 49 orphans in Syria to confirm their relations to Russian citizens and clear their return home, Russia’s top children’s rights official said Thursday.

Under a program spearheaded by Chechen leader Ramzan Kadyrov, Russia has worked on returning women and children linked to Russians who fought for the Islamic State in Syria and Iraq. Kadyrov last year called for mass DNA tests in his majority-Muslim region to help repatriate Russian children from the war-torn countries.

Russia was granted access to 49 orphans held in Syrian jails and camps for DNA testing, Interfax cited presidential children’s rights ombudsperson Anna Kuznetsova as saying. Some children are said to be younger than 6 months.

Kuznetsova said that Russian citizens identified as the children’s relatives have also submitted DNA samples to establish family kinship. 

An Emergency Situations Ministry flight from neighboring Iraq with 32 Russian children on board is expected soon, Kuznetsova said. The remaining children, she added, will return from Iraq by civilian aircraft.

Meanwhile, the chief of Russia’s Federal Security Service (FSB) has warned that adult Islamic State fighters should undergo close vetting by the countries where they’re being held as well as by Russia before being cleared for repatriation.

“Only then will we make a determination. Other than that, we’re firmly against just [letting them] come,” Interfax quoted FSB director Alexander Bortnikov as saying.

“The children are a different matter,” Bortnikov added.

Islamic State is a terrorist organization banned in Russia.