It has been 30 years since the United States signed the United Nation’s Convention on the Rights of the Child, a human rights treaty meant to protect children around the globe. In honor of this anniversary, a U.N. human rights expert was in Geneva on Monday (November 18) to discuss a new study on the current treatment of children around the world, NPR reports. In it, the author writes that the United States is guilty of “inhuman treatment for both the parents and the children.”

Manfred Nowak, a human rights lawyer based in Vienna, Austria, wrote “Global Study on Children Deprived of Liberty,” which says the Trump administration’s family separation policy is “absolutely prohibited” by the Convention on the Rights of the Child. The study was commissioned in October 2016.

“And there are still quite a number of children that are separated from their parents—and neither the children know where the parents are, nor the parents know where the children are. So that is something that definitely should not happen again,” Nowak said during his remarks, per NPR.

The study “estimates that the U.S. is still holding more than 100,000 children in migration-related detention,” NPR reports. Nowak added in his speech, “That’s far more than all the other countries where we have reliable figures.” In fact, he said the U.S. incarcerates more children than anywhere else in the world:

“In general, the incarceration rate in the United States is very high also of adults, and that you see also with children. So it’s about 60 out of 100,000” children, Nowak said. “And that is the highest that we could find, followed by others like Bolivia, or Botswana, or Sri Lanka….”In general,” Nowak said, “the North American region is the one with the by far highest regional imprisonment rate of children.”

As NPR reports, the U.S. signed but never ratified the Convention on the Rights of the Child, which means the convention’s rules “do not formally apply to the United States of America.” However, Nowak still believes the country should be held accountable for its atrocities thanks to other civil rights treaties.

“In my opinion, the way, how they were separating infants from the families only in order to deter irregular migration from Central America to the United States of America, for me, constitutes inhuman and degrading treatment, and that is absolutely prohibited” by those other international treaties, he said.

“I am deeply convinced that these are violations of international law,” Nowak said. He added, “The same is also true for the high number of children being deprived of liberty in the administration of justice” in the U.S.

Nowak emphasized the importance of valuing children in his talk. “Children should live, or grow up, in families—their own families, foster families, family-type settings,” he said, “and not in institutions where they’re in fact deprived of liberty, where there’s strict discipline, there’s a lot of violence. There’s no love.”