More than 100 migrant children have been returned to a Texas border station just a day after being transferred, US border officials say.
About 250 migrant children were moved from the overcrowded centre after lawyers granted access by a judge said the children were "severely neglected".
The top US border official meanwhile has said he is stepping down.
It comes as the number of migrants apprehended at the border surged in May to the highest level since 2006.
