In the wake of reuniting migrant families separated under the Trump administration, lawyers working to reach the said families tracked the parents of at least 54 migrant children in the past month under the Biden administration. 

A court filing revealed the number of tracked parents of migrant children on Wednesday, NBC News reported. The court filing comes as the Department of Homeland Security (DHS) announced the effort of the Biden administration in reuniting entire migrant families that the previous administration separated.

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More Migrant Families Need to be Reunited by Biden Administration

In addition to 54 migrant children's parents tracked down, the parents of the other 391 migrant kids have yet to be contacted. Forbes noted that in April, the total number of migrant children with untracked parents was 445.

Four migrant families separated at the Mexico border were also reunited earlier this month. It was announced on the same day that the DHS broadcasted the efforts of the Biden administration in reuniting entire families separated under Trump administration.

In February, Lee Gelernt, a lawyer from the American Civil Liberties Union (ACLU), confirmed with Forbes that searching for the remaining families will be "extremely challenging" because many parents of the migrant kids are in foreign countries.

Another factor that will make the process challenging is that many children live with their relatives and foster families.

Lawyers from the ACLU and other groups, whom a federal judge commissioned to reach the migrant families separated by the Trump administration, reported that out of the 391 migrant kids, the parents of the 227 had been deported, while 100 are located somewhere inside the United States, and 14 have no contact information that the government has provided.

Authorities did not provide further details on the remaining 50.

"We are working steady progress finding families but there is still a long way to go," said Gelernt. 

Gelernt hoped that they could find every last family "and that the pace will pick up," emphasizing that on-the-ground searches will now be possible due to the availability of the COVID-19 vaccine.

How Many Families Were Separated Under the Trump Administration?

Between 2017 and 2018, at least 5,500 migrant families were separated after crossing the border. The task force set up by the Biden administration to reunite the migrant families noted that at least 1,000 migrant children remain separated from their families, including the 391 whose parents remain unidentified. 

The said separation resulted from the zero-tolerance policy where the government tried to prosecute all adults who crossed the border illegally.

It can be remembered that the task force established by the Biden administration was working on a database and correcting the inaccuracies in the file concerning the issue provided to them. 

Furthermore, the task force was also reported reviewing "additional trove documents" intended for family reunification in the coming months.

The Biden administration has pledged to reunite migrant families separated under the Trump administration, either in the United States or their home countries.

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WATCH: ACLU Filing: Parents of 545 Separated Migrant Children Still Unable to be Reached - From CBS This Morning