Washington — The Trump administration on Wednesday unveiled a sweeping plan to detain migrant families and children for longer periods of time than currently allowed, touting a final regulation that would overhaul the immigration detention system in the U.S. and scrap a longstanding court settlement.

For more than two decades, the court settlement known as the Flores Agreement has governed the care of migrant children in U.S. custody. The 1997 agreement sets sweeping standards for the treatment of unaccompanied migrant children, from housing to medical care, as well as education, nutrition and hygiene. In more recent rulings, the federal judge overseeing the settlement has also effectively prohibited the government from detaining for more than 20 days families apprehended with children.

But the new Department of Homeland Security (DHS) regulation, a draft of which was published last year, would give immigration authorities more leeway in detaining families with children for longer, and modify the standards of care for unaccompanied children set forth by the 1997 settlement. The administration believes these changes would render the deal obsolete.

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Under the administration's rule, which will be published in the Federal Register Friday and would go into effect 60 days later, there would not be a limit to the number of days families with children could be detained. But officials acknowledged that court challenges will likely delay the implementation of the regulation, which also needs to be approved by the federal judge overseeing the Flores litigation.

In a briefing Wednesday, Acting Homeland Security Secretary Kevin McAleenan said there is "no intent" to hold families for "a very long time," and vowed that the U.S. government would treat migrant children with "dignity, respect and special concern in concert with American values." He suggested that if cases involving detained families could be adjudicated at the same pace they were in 2015, they'd be in custody for an average of about 50 days.

Central American asylum seekers who illegally crossed the Rio Grande nearby wait to be transported to a processing facility after turning themselves in to Border Patrol in Los Ebanos, Texas, on June 28, 2019. LOREN ELLIOTT / REUTERS

Peter Schey, the lead attorney for the team representing thousands of unaccompanied migrant children in the Flores case, said the terms of the Flores Agreement prohibit the government from implementing rules that undermine it. In a Tuesday night interview with CBS News, Schey said the only way to terminate the settlement would be to issue a final regulation that codifies the full agreement into federal law.

Schey said he expects the judge that oversees the Flores case to reject the administration's efforts.

"These regulations do not implement the settlement. In fact, it abrogates the settlements. And so I think their efforts will be futile," said Schey, who had not yet seen the final regulations, but reviewed a draft published in September 2018.

He accused the White House of playing politics with children's well-being.

"They know that the only way the can terminate the settlement is by coming out with regulations that institutionalize it, but they have a history of criticizing the settlement," Schey said. "So what is this? I think it's a politicization of the treatment of children. It's part of running for reelection. That's what it's about."

Since President Trump took office in 2017, his administration has railed against the court agreement, saying it hampers its efforts to deal with large influxes of migrants like the recent months-long surge of Central American families and children journeying towards the U.S. Officials have maintained that migrant adults bring their children with them to the U.S. because they know immigration authorities cannot detain families with children for a prolonged period of time. Instead, families are typically released after days in detention and given a notice to appear in court.

According to a Homeland Security official, the administration hopes to eliminate what it sees as an "incentive" by detaining families until the end of their immigration proceedings. The regulation would not establish a cut off date for the detention of families with children, but the official maintained it would not lead to indefinite detention, as advocates fear.

The judge overseeing the Flores litigation, U.S. District Court Judge Dolly Gee, said in 2015 that the government needed to transfer children to "state-licensed facilities" within 20 days. But states operate facilities to house children, not families, which meant that the 20-day requirement became a time limit for the detention of families.

Through the new rule, the administration hopes to circumvent the 20-day detention limit by creating a federal licensing system to authorize facilities the government can use to detain families with children.

The U.S. government currently only has three facilities designed to detain and house migrant families, two in Texas and one in Pennsylvania. Under the new regulation, the Homeland Security official said these facilities would be subject to an audit from a unspecified third party that would ensure the locations comply with licensing standards.

The official conceded that the agency expects the rule to quickly be challenged in court. The administration will argue that the rule does not amount to indefinite detention because authorities will offer migrant families bond hearings and the opportunity for parole, as long as they don't pose a threat to communities, the official added.

Migrants from Brazil turn themselves into Border Patrol agents to claim asylum after crossing the Rio Grande as seen from Ciudad Juárez, Mexico, on June 12, 2019. Herika Martinez / AFP/Getty Images

The provisions of the rule would modify the guidelines currently followed by employees of the Department of Health and Human Services (HHS), Customs and Border Protection (CBP) and Immigration and Customs and Enforcement (ICE) — the three federal agencies which house detained migrants.

Border Patrol agents, overseen by CBP, are typically the first to encounter and apprehend unaccompanied migrant children and families with children near the U.S.-Mexico border. The agency is supposed to care of them for no longer than three days before transferring unaccompanied minors to HHS and families to ICE.

Most families in ICE custody are released before 20 days in detention because of Gee's 2015 ruling, while most unaccompanied minors usually spend weeks or months in privately run shelters that are overseen by HHS and designed to take care of children until the government finds a sponsor for them — typically relatives who live in the U.S.

The regulation issued Wednesday is the latest effort by the Trump administration to radically reshape the country's immigration system, dating back to Mr. Trump's first week in office, when the president issued an executive order seeking to limit the number of refugees who could be admitted to the country — in particular those from seven predominantly Muslim countries. That rule would be the first of many under this administration to face significant legal challenges.

More recently, the administration announced a plan to restrict lawful permanent resident status, commonly known as green cards, to applicants who do not receive certain public benefits. Sixteen states have since sued to block the rule since it was published on Aug. 14.

In this March 14, 2019, file photo, families who crossed the nearby U.S.-Mexico border near McAllen, Texas, are placed in a Border Patrol vehicle. AP

The Flores Agreement stems from a 1987 case in which Jenny Lisette Flores, a 15-year-old girl from El Salvador, and three other migrant children filed a class action lawsuit against the government over poor detention conditions for minors in U.S. custody. Flores and the other children alleged they were housed in brutal conditions, in razor wired-fenced facilities with adult men and women, while being subjected to abuse and routine strip searches.

In 1997, both parties reached an agreement that set standards for the care of migrant children in the custody of the Immigration and Naturalization Service (INS), a now-defunct branch of the Justice Department.

"Following arrest, the INS shall hold minors in facilities that are safe and sanitary and that are consistent with the INS's concern for the particular vulnerability of minors," the agreement reads. "Facilities will provide access to toilets and sinks, drinking water and food as appropriate, medical assistance if the minor is in need of emergency services, adequate temperature control and ventilation, adequate supervision to protect minors from others, and contact with family members who were arrested with the minor."

Since the INS was abolished in 2003, the Department of Homeland Security (DHS) has taken up most of its functions and is bound to the parameters set forth by the Flores settlement. Over the years, immigration lawyers and advocates have accused Republican and Democratic administrations of violating the agreement and detaining migrants in poor conditions.

Starting in 2015, Gee, the judge, reviewed several accounts from minors and their parents of living conditions in Customs and Border Protection (CBP) facilities during the Obama administration. In several rulings, she found the government had not provided migrant minors "safe and sanitary" living conditions. Facilities near the U.S.-Mexico border were overcrowded and the children living in them did not have access to toothbrushes and soap, could not sleep because of the cold and were not given enough food.

In 2017, Gee also ordered the creation of an independent monitor to ensure the government adhered to the Flores agreement.

The Trump administration recently appealed one of Gee's rulings to the U.S. 9th Circuit Court of Appeals, accusing the lower court judge of legislating from the bench by ruling that the government should, among other things, provide migrant children in its custody toothbrushes and soap. The administration contended, in a hearing that went viral, that Gee modified the Flores agreement with her order, as the text of the settlement does not include word-for-word references to "soap" or "toothbrushes."

The 9th Circuit has repeatedly affirmed Gee's decisions in the case.

Although the conditions reviewed by Gee when she made her decision in 2017 were documented during President Obama's tenure, lawyers and immigrant advocates have also denounced the conditions in migrant detention centers operated by the Trump administration.

Just this years, lawyers detailed harsh conditions faced by approximately 250 migrant children at an overcrowded Border Patrol station in Clint, Texas. The DHS inspector general also found squalid conditions in several detention centers for migrant families and children in Texas, including "serious" overcrowding, minors going without hot meals for days and detainees begging not to be returned to their cell

At least seven migrant children have died in U.S. custody or shortly after being released under Mr. Trump's tenure.

Clare Hymes contributed reporting.