Up to 2,100 children who were split up from their families near the U.S.-Mexico border during the Trump administration may still be separated from their parents, according to a Department of Homeland Security (DHS) report prepared for President Biden.

It is unclear whether they can be reunited, the department says.

Some of those children may have found a way to reunite with their parents, but the U.S. government has no records documenting their reunifications, the Family Reunification Task Force created by Mr. Biden said in its first progress report, which was made public Tuesday.

Five of the migrant children who have yet to reunite with their parents remain in the custody of the Department of Health and Human Services (HHS) because officials have not been able to locate family members in the U.S. willing to care for them, the report revealed.

The task force said U.S. border officials separated at least 3,913 migrant children between the summer of 2017 and the end of former President Trump’ tenure as part of efforts to deter migration. Before Mr. Biden established the DHS-led task force, 1,779 of those children were reunited with their parents due to a federal court case and the work of advocacy groups.

DHS said it is working to verify how many of the 2,137 children with no records of reunification are still separated from their parents. 

So far, the task force has facilitated the reunification of seven families who had been separated under Mr. Trump. DHS said it expects to facilitate the reunification of an additional 29 families in coming weeks.

According to the report, U.S. Citizenship and Immigration Services (USCIS) has approved 37 requests to allow the parents and siblings of separated children to enter the U.S. so they can reunite on American soil – a move the Trump administration opposed.

“We are presuming that separation was an extreme harm and that reunifying separated parents and children serves a compelling humanitarian interest and a significant public benefit. So we are beginning with that presumption but then each case will be weighed case by case,” a senior DHS official said regarding the requests. 

DHS said it anticipates U.S.-based reunifications to ramp up in the next few months.

“The Department of Homeland Security is committed to the relentless pursuit of reunifying families who were cruelly separated by the previous Administration,” said Homeland Security Secretary Alejandro Mayorkas, who Mr. Biden tapped to lead the task force. “When we reunified the first seven families last month, I said that this was just the beginning.”

More than 1,600 separated parents and nearly 400 children were deported to their home countries, the task force revealed in its report, noting that families were deported together in only 2 percent of the cases.

Lee Gelernt, the American Civil Liberties Union (ACLU) lawyer overseeing the federal court case over the Trump-era separations, urged the Biden administration to speed up the reunifications.

“We would really have liked to see more progress by now but intend to look forward to ensure the government picks up the pace,” Gelernt told CBS News. “The president has called this a historic moral stain on the country and therefore, we believe the government needs to do whatever it takes to get these families reunited.”

In addition to the 3,900 separations deemed to fall under the purview of the task force, DHS said it is analyzing 1,700 more separation cases to determine whether they were justified.

Once in the U.S, reunited families have access to mental health services through HHS. The task force said it is also considering offering families case management, clinical treatment, parenting support and other services. 

Eligible separated families are being granted three-years of protection from deportation to try to acquire work permits. While the periods can be extended, the relief is temporary and does not allow families to apply for permanent legal status in the U.S. If families lose their asylum cases, they could face deportation.

“We will be looking into what is available for long-term status,” the DHS official said. “Right now, we can’t guarantee any long-term status for people but we will look at avenues and procedures through which they can apply for existing benefits.”

Advocates have been pushing the Biden administration to place separated families on a pathway to U.S. citizenship.

“They have to have a sense of security and permanency,” Gelernt said. “We are hopeful that the government will do the right thing and not subject these families to deportation.”