On Tuesday (June 5), the Office of the United Nations High Commissioner for Human Rights called on the Trump administration to immediately end its practice of separating families seeking asylum at the United States-Mexico border. The practice is part of the federal government’s “zero tolerance” immigration policy that has separated some 650 children from their families since early May.

United Nations officials said that the Central American migrants crossing the border are in most cases fleeing violence and gang persecution targeting youth—conditions that warrant international protection.

“The U.S. should immediately halt this practice of separating families and stop criminalizing what should at most be an administrative offense—that of irregular entry or stay in the U.S.,” U.N. human rights spokesperson Ravina Shamdasani said in a statement. “We call on the U.S authorities to adopt non-custodial alternatives that allow children to remain with their families and fulfill the best interests of the child, their right to liberty and their right to family life.”

Last week, a coalition of immigration advocates appealed to another international body, the Inter-American Commission on Human Rights (IACHR), for help in ending the “unjustifiable” practice of family separation at the U.S.-Mexico border. Their request asks IACHR to call on the U.S. Department of State to end the practice.

The coalition joins evangelical organizations, child welfare experts, and other immigration advocates who have urged the administration to stop separating families. Trump, in turn, has falsely blamed Democrats for the separation policy.

In early May, Attorney General Jeff Sessions unveiled the administration’s “zero tolerance” policy aimed at deterring undocumented immigration. He said: “If you are smuggling a child, then we will prosecute you and that child will be separated from you as required by law.” 

After hearing from U.S. civil rights groups, the U.N. on Tuesday said it was concerned about the policy, which has led to young children being separated from their parents, in many cases with no notice and with parents provided no information about their children’s whereabouts.

“Detention is never in the best interests of the child and always constitutes a child rights violation,” Shamdasani said.