Washington (CNN) The White House is reviewing a plan that could nullify a settlement that immigrant children that arrive with their families be released from custody within 20 days, a rule they have blamed for their separation of thousands of families at the border.

The action to finalize regulations on the topic, revealed in a government database, comes after repeated attempts to change the Flores Settlement Agreement have been resoundingly rejected by a federal judge and amid continuing fallout over the Trump administration's related decision to separate families at the border.

The Trump administration has made the Flores settlement a frequent target of its ire -- blaming the agreement for its decision to implement a policy at the border that resulted in thousands of families being separated. It has also repeatedly said only Congress can act to overrule the settlement. But lawmakers have shown little appetite to do so and have so far failed to pass any immigration legislation under this administration.

Key provisions of the agreement dictate minimum standards of care of immigrants in detention, as well as requiring that children who arrive with their families be released from custody within 20 days unless their parent agrees to them being held longer. But three weeks is faster than their immigration court cases can be processed, leading the Trump administration to complain the agreement forces them to either release the families together or separate them.

The agreement, along with a 2008 law, is designed to protect immigrant children who end up in government detention or cross the border illegally. The administration has blamed those protections for changes in migration patterns , pointing mainly to the fact that the two things occurred in roughly the same time period.

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