Chicago (CBS) – A coalition of 12 attorneys general, including Illinois Attorney General Lisa Madigan, sent a letter to the federal government demanding immediate reversal of a policy that has prevented immigrant families from reuniting.

The letter, sent Thursday to U.S. Secretary of Health and Human Services Alex M. Azar II and U.S. Secretary of Homeland Security Kirstjen Nielsen, said the policy requires prospective sponsors of unaccompanied migrant children and their entire households to submit to fingerprinting and background checks. This information is automatically shared with Immigration and Customs Enforcement (ICE).

This has delayed and prevented the placement of unaccompanied migrant children with their family members or other appropriate sponsors living in the United States and as a result, kept children in prolonged federal detention, Madigan and the other attorneys general said.

“Migrant children being subjected to lengthy, prison-like detention in federal tent cities is outrageous,” Madigan said. “The administration’s inhumane immigration policies are tearing apart families, traumatizing children and must stop.”

The letter said the policy imposes “unjustified burdens” in the sponsorship process and leaves many prospective sponsors with an “untenable choice” of either leaving children in federal custody or coming forward and possibly exposing themselves or loved ones to immigration enforcement.

Madigan and the other attorneys general said the requirements allege the true motive for collecting and sharing their information has been to detain and deport immigrants.

The Office of Refugee Resettlement agreed earlier this year to impose these requirements although there is a lack of evidence these would make children safe, according to the letter.

There are more than 13,000 children in detention, which has pushed shelters past capacity. The federal government has moved children to a makeshift “tent city” near Tornillo, Texas, the letter states, and the current policies will continue to increase the reliance on detention facilities like this one.

In April 2018, the federal government announced a “zero tolerance” policy requiring the immediate separation of children from their parents and the criminal prosecution of adults who entered the U.S. without permission, including those seeking asylum.

In June 2018, Madigan and a coalition of 18 attorneys general filed a lawsuit against the Department of Justice, DHS and administration officials over the policy.

Other signees of the letter include attorneys general from California, New York and Massachusetts.