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FIRST ON FOX: Twenty-one Republican-led states suing the Biden administration to stop the Title 42 public health order are now seeking a temporary restraining order to prevent any lifting of the order ahead of the May 23 rollback date.

Three states, Arizona, Louisiana and Missouri, initially sued the Biden administration earlier this month over the move to end Title 42, which was implemented by the Trump administration in March 2020 in response to the COVID-19 pandemic and allows for the rapid expulsion of migrants at the border, on May 23.

REPUBLICAN STATES SUE TO STOP BIDEN ADMIN'S LIFTING OF TITLE 42 BORDER POLICY

Soon after, more states signed onto the lawsuit, bringing the number to 21.

"This suit challenges an imminent, man-made, self-inflicted calamity: the abrupt elimination of the only safety valve preventing this administration’s disastrous border policies from devolving into an unmitigated catastrophe," the complaint states.

"Once again the Biden Administration is thumbing its nose at the American people and the rule of law," Arizona Attorney General Mark Brnovich said in a statement to Fox News Digital Thursday. "It cannot be allowed to continue in this recklessness."

Border officer immigrants

June 16, 2021: A Texas Department of Public Safety officer in Del Rio, Texas directs a group of migrants who crossed the border and turned themselves in. (AP Photo/Eric Gay, File) (AP Photo/Eric Gay, File)

The public health order was implemented in March 2020 due to the COVID-19 pandemic and has been used since to expel a majority of migrants at the border. Of the more than 221,000 migrants encountered at the border in March, 50% were expelled under Title 42.

The additional request for a temporary restraining order filed Thursday is intended to stop any move by the Biden administration to implement the revocation of Title 42 ahead of that May 23 date -- and prove that it has been implementing Title 42.

Fox News reported on Wednesday that due to limited space on expulsion flights, Border Patrol has already stopped using Title 42 to expel some migrants from the Northern Triangle countries of Guatemala, Honduras and El Salvador. 

BORDER PATROL NOT USING TITLE 42 TO EXPEL SOME NORTHERN TRIANGLE MIGRANTS AHEAD OF ITS MAY 23 END: SOURCES

Border Patrol sources told Fox News that it is instead processing them via Title 8 and expedited removal. The sources said that the order is technically still in place for those migrants, but only as long as there is space on Title 42 expulsion flights. If those flights are full, the migrants from those countries are put into expedited removal.

Expedited removal allows authorities to quickly remove a migrant without a hearing if they have recently entered the U.S. illegally. However, the sources told Fox News that if a migrant claims they have a fear of persecution, the removal order is changed to a Notice to Appear -- meaning they are released into the United States with a future court date. They said that migrants are already spreading the word about what to say to get released into the U.S.

Customs and Border Protection (CBP) told Fox News in a statement that the expulsions under Title 42 for those nationalities "remain in effect" and denied that it has stopped the order for migrants from those countries.

"In accordance with the CDC order, non-citizens from certain non-contiguous countries are expelled via aircraft as soon as possible but the expulsion is delayed," a spokesperson said. 

"The time required to coordinate flights for the large number of migrants falling into the delayed expulsion category necessitate detention times outside the isolation period for the COVID-19 virus. In lieu of paroling this population or issuing a notice to appear and releasing on their own recognizance, CBP is processing the migrants for expedited removal," they said. "The migrants are detained by [Immigration and Customs Enforcement and Removals Operations] pending their removal."  

Fox News' Bill Melugin contributed to this report.