The Trump administration has unveiled new rules that allow the US government to detain migrant families indefinitely while their asylum cases are judged.

Kevin McAleenan, the acting secretary of homeland security, said that the administration plans to withdraw from the Flores settlement, a two-decade-old court agreement that does not allow the government to detain children in immigration jails for more than 20 days and specifies the level of care they must receive while there.

Despite knowing that the new rules will be challenged in the courts, the White House and Donald Trump have pushed the Department of Homeland Security to replace the agreement. The president and his adviser Stephen Miller say the settlement entices families to attempt to cross the border illegally. The administration has previously faced criticism for a now-defunct policy of separating children from their parents at the border.

The new regulations, which were shown to a handful of selected reporters on Tuesday night, would seek to permanently establish “standards of care for children and families”, according to Mr McAleenan.

The Trump administration’s latest move marks the third major regulatory change on immigration in little more than a month. All during an unsettled period when senior immigration officials hold “acting” titles as they lack Senate confirmation.

On 15 July the administration unveiled a rule barring almost all immigrants from applying for asylum at the border with Mexico and on 12 August it announced regulations allowing visas and permanent residency only for those who make enough money.

Mr Trump also said today that his administration was looking at ending the right of citizenship for US-born children of non-citizens. It is a right enshrined in the country’s constitution. The 14th amendment, passed after the Civil War to ensure that black Americans had full citizenship rights, granted citizenship to “all persons born or naturalised in the United States.”

“We’re looking at that very seriously, birthright citizenship, where you have a baby on our land, you walk over the border, have a baby – congratulations, the baby is now a US citizen ... It’s frankly ridiculous,” Mr Trump said.

Trump has made cracking down on immigration a central plank of his presidency and re-election campaign, but many of the administration’s sweeping rule changes and executive orders have been stymied by the courts.

In Wednesday’s press conference, Mr McAleenan steered clear of detailing the inhumane conditions in the current detention camps, including children being barred from showering and being denied medicine. Instead, the acting secretary painted a rosy picture of the new centres, which he said would include “soccer fields” and “volleyball courts”, as well as school for children “five days a week”.

But the conditions of the camps might cause more alarm for human rights advocates, as the new regulations require less oversight. The new rules eliminate a requirement that federal detention centres for immigrant families must be licensed by states. Instead, the centres would only have to meet standards set by Immigration and Customs Enforcement.

'Dangerous' overcrowding of migrants in US border facilities Show all 6 1 /6 'Dangerous' overcrowding of migrants in US border facilities 'Dangerous' overcrowding of migrants in US border facilities Photos of detained migrants crowded into cells at the US border - with one holding up a sign reading simply "help" - have been released as part of a new report warning of "dangerous" overcrowding. The memo was sent to the Department of Homeland Security by its Inspector General, containing photos taken at border facilities in the Rio Grande Valley over a week in June DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Eighty-eight adult males held in a cell with a maximum capacity of 41, some signalling prolonged detention to OIG Staff on June 12 DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Overcrowding of families observed by OIG on June 11, at a border patrol facility in Weslaco, Texas DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Migrant families overcrowding a border patrol facility on June 11 in McAllen, Texas DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Fifty-one adult females held in a cell designated for male juveniles with a capacity for 40 at Border Patrol’s Fort Brown Station DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Migrant families overcrowding a border patrol facility on June 11 in McAllen, Texas DHS/OIG

Despite the previous family-separation policy, Mr Trump defended the new rules, claiming: “I’m the one that kept the families together.”

When questioned on how long the families were expected to stay detained under the new rules, Mr McAleenan said that families had been held for “under 50 days” before. But did not give a new estimate of how long families will be held for in future.

The rules will supposedly take effect 60 days after they’re filed on Friday, but are expected to be challenged in court immediately. The American Civil Liberties Union has already issued a statement condemning the rules, tweeting: “The government should NOT be jailing kids, and certainly shouldn’t be seeking to put more kids in jail for longer.”

“This is yet another cruel attack on children, who this administration has targeted again and again with its anti-immigrant policies,” the tweet continued. “Congress must not fund this.”

Democrats in Congress and immigration advocates also attacked the move. “The cruelty of the Trump administration knows no bounds. Make no mistake: this new rule is about letting President Trump and Stephen Miller keep children in awful conditions for longer periods of time and continue the administration’s horrid treatment of innocent migrant families fleeing unthinkable hardship,” the leading Democrat in the Senate, Chuck Schumer, said in a statement.

Peter Schey, a lawyer for the immigrant children in the Flores case and president of the Centre for Human Rights and Constitutional Law, said if the regulations don’t match the settlement in that case, “they would be in immediate material breach, if not contempt of court”.

“I think all these things are now part of the 2020 campaign,” Mr Schey told the Associated Press.

The administration has framed the policy as a humane approach to a record number of mostly Central Americans having sought asylum in the United States.

“To protect these children from abuse, and stop this illegal flow, we must close these loopholes. This is an urgent humanitarian necessity,” Mr Trump said in a statement.