The U.N.’s top human rights official called the United States’ practice of separating migrant families at the border “abuse” and called for an immediate stop to the practice, according to a Monday New York Times report.

“The thought that any state would seek to deter parents by inflicting such abuse on children is unconscionable,” said Zeid Ra’ad al-Hussein, the U.N. high commissioner for human rights.

He reportedly cited a statement made by American Association of Pediatrics President Dr. Colleen Kraft when she called the practice “government-sanctioned child abuse.”

His office has decried the practice before, reportedly saying that it is in violation of the children’s rights and international law. This prompted admonishment from U.S. ambassador to the U.N. Nikki Haley who accused his office of “ignorance” and “hypocrisy,” per the New York Times.