The New York Civil Liberties Union has launched a national putative class action claiming that a Trump administration policy on fingerprint-based background checks for immigrant household members has led to the highest level in history of migrant children being locked up in government custody away from their parents.

Calling the policy and the “predictable” administrative delays that come with it “unconscionable,” the civil rights group filed its lawsuit in the U.S. District Court for the Southern District of New York on Tuesday. The 23-page suit, which the group brought in conjunction with Morrison & Foerster and the National Center for Youth Law, names as plaintiffs six migrant children currently in custody who allegedly have been waiting between two weeks and nearly four months for the results of their sponsors’ fingerprint background checks.