The Trump administration said Thursday it will seek to keep some undocumented immigrant children in detention for far longer than currently allowed, a move that would have sweeping implications for the families and for the immigration detention system.

The move comes on the heels of the administration’s decision this spring to separate families at the border as part of its “zero tolerance” prosecution policy, which resulted in more than 2,500 children being separated from their parents for weeks to months at a time.

The more than 200-page proposed regulation would circumvent a court settlement that has, for 20 years, set standards for the care of children in immigration detention, freeing the administration to have much broader authorities over how undocumented immigrant children are treated in its care.

But immigration advocates argue the changes amount to flouting the best interests of children, which they say was the original purpose of the settlement.