Democratic politicians reacted with anger Wednesday to a CBS News report revealing that "well over 4,000" migrant children could be held in government custody indefinitely.

The number of children, designated "Category Four" by the Office of Refugee Resettlement (ORR), was divulged in an exclusive interview with ORR Director Jonathan Hayes. The children are among the more than 10,000 currently considered "unaccompanied" either because they were apprehended alone after crossing into the U.S., or because authorities separated them from the relatives or other adults they were traveling with.

Children are labeled Category Four when the government says it can find no approved sponsors to take them in. While most unaccompanied migrant children are ultimately placed with sponsors — parents, relatives or family friends who live in the United States — the 4,000 Category Four children can remain in government custody for years.

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The number of children labeled Category Four as grown dramatically under the administration of President Donald Trump, according to former ORR officials who worked for the agency during the Obama administration.

"We cannot accept this," tweeted former Secretary of State Hillary Clinton, who was the Democratic nominee for president in 2016.

We will not and cannot accept this. https://t.co/9WLFsnzpTL — Hillary Clinton (@HillaryClinton) July 24, 2019

In a statement to CBS News, Rep. Debbie Wasserman Schultz, D-Florida, blamed a series of immigration policies enacted by the Trump administration for the increase.

"Trump's zealous apprehension program and family separation policy, along with the administration's restrictive and draconian policies for unaccompanied minors has created a situation in which thousands of so-called Category Four kids are tragically and unnecessarily, falling through the bureaucratic cracks. The Administration's information-sharing agreement between ORR and DHS has made the problem worse, as it scares potential sponsors away from ever coming forward," Wasserman Schultz said.

The congresswoman — who is among a trio of Democratic representatives who have repeatedly sought to inspect the nation's largest unaccompanied children shelter because it is within or near their districts — called for the federal government to expand the pool of people who can sponsor Category Four children.

People who did not have personal relationships with the families of Category Four children are currently ineligible to take in those children, due to an ORR policy known as the "pre-existing relationship" rule. However a federal judge recently wrote the rule's implementation might violate federal law. In that case, a child who was deemed Category Four after his father was deported won the right to live with a family his father met after their separation.

"Children spending their entire childhood languishing in a child detention facility until they can be arrested and face deportation once they turn 18 is monstrous," Wasserman Schultz said. "The Trump Administration must expand the categories of eligible sponsor households, including possibly allowing American families to sponsor a child detainee, many of whom would like to welcome these children into a loving home."

Another member member of Congress, Tim Ryan, D-Ohio — who along with Wasserman Schultz is on the House Appropriations Committee — tweeted a quote from the CBS News report and called the treatment of Category Four children "child abuse."

"[This] is not a healthy situation for children, not knowing what their future is, not having access to recreation, education, being separated from their family members. And these children are for the most part already traumatized" This is state-sponsored child abuse. https://t.co/gQUm38Jkdo — Congressman Tim Ryan (@RepTimRyan) July 24, 2019

Sen. Jeff Merkley, D-Ore., whose book about refugees will be published in August, said in a statement to CBS News that the government should allow new avenues for Category Four children to find and be placed with sponsors.

"The idea that vulnerable children could be held by the U.S. government for years on end is incredibly disturbing. Children belong in homes, parks, and schools, not locked up by our government. The administration needs to stop scaring away potential sponsors by threatening to share their information with ICE," Merkley said.

The Senator added that he's heard from constituents who want to take children in.

"Additionally, for any children who truly do not have family or friends in the U.S., we should ensure that there is a pathway to be sponsored by caring families who want to take these children in," Merkley said. "In the last year alone, I have heard from hundreds of Oregonians who want to help these children and get them out of these child detention centers. The notion that there is no alternative to holding them for years on end is completely unacceptable and morally wrong."

CBS News sent ORR questions covering a variety of topics related to Category Four children. The agency did not respond.