Some 711 migrant children taken from their parents at the US-Mexico border have not yet been returned to them, despite a court-ordered deadline.
US government lawyers said the children were not eligible to be reunited with their parents.
The reasons given included a lack of confirmed family ties, or a parent having a criminal record or a communicable disease.
In 431 cases the parents were no longer in the US, a court filing said.
US officials separated more than 2,500 children from undocumented adults at the border with Mexico earlier this year, in a “zero tolerance” crackdown on illegal immigration.
But it was suspended by President Donald Trump last month after a fierce backlash.The Trump administration says it has reunited more than 1,800 migrant children with family members. Its lawyers argue that it met the legal deadline, as the 711 remaining children are not “eligible” to be given back.