The US Departments of Homeland Security and Health and Human Services have said they have reunified about 538 unauthorized immigrant children who have been separated from their families by the Trump administration’s “zero-tolerance” prosecution policy — out of a total of 2,300 children separated from their parents.

But legal and advocacy groups on the ground in Texas say that number is difficult to verify. For instance, the Texas Civil Rights Project, whose attorneys represent close to 400 unauthorized immigrant families, has counted only four reunifications.

Speaking about the more than 500 families the Trump administration has claimed to have reunified, the Texas Civil Rights Project released a statement saying, “We do not have confirmation of these and have received conflicting reports regarding reunification.”

Immigration attorneys and advocates on the ground in Texas are suspicious of the administration’s numbers, given its shifting answers.

“On the ground, no one knows what’s going on,” said Lee Gelernt, deputy director of the American Civil Liberties Union Immigrants’ Rights Project and one of the lead attorneys suing the Trump administration on the family separation issue.

Even if the government has reunited more than 500 kids with their families, it’s likely because these individuals were recently detained — and therefore the parents and children were being held in close proximity while the parents were taken to court. In other words, the kids hadn’t yet been taken into custody by the Office of Refugee Resettlement, which places separated minors in shelters and facilities all over the country.

But Trump’s family separation policy had been going on for weeks — and the future of the kids who have been in federal custody longer and sent to federally run shelters all over the country is much less certain.

Advocates for the immigrants say a huge barrier to reunification is the fact that parents and children are being detained by two completely different government agencies: Parents are held by Immigration and Customs Enforcement (or ICE, which is part of the Department of Homeland Security or DHS), and children, by the Office of Refuge Resettlement (ORR, part of the Health and Human Services infrastructure known as HHS).

“These two different agencies have the pieces of families and no communications lines established at all,” said Bethany Carson, an immigration researcher and organizer for Grassroots Leadership who works with detained mothers in Texas. “There’s no process that’s being followed for reunifying these women with their kids.”

Huge barriers to family reunification

Carson and her colleagues primarily work with migrant women who have been detained by the federal government in the women’s-only Hutto Detention Center in Taylor, Texas.

The government officials that the women in Hutto typically interact with are their ICE deportation officers. Carson said she believes ICE “doesn’t have a lot of interest in actually connecting them with their kids.”

Carson said she knows of women who have asked their deportation officers how can they talk to their kids, only to have the officers respond that it’s not their job. Some women have been able to speak to their children by phone, but the most they’ve been able to talk to them is twice a month. Other women have no idea where their kids are.

The other problem for women detained in Hutto is that while they can call places outside the detention center, they cannot receive incoming calls. This means that even if an attorney or a government official was trying to contact these mothers with information about their children, they would not be able to get the call.

DHS and HHS insist they are trying to fix these problems as they aim to reunite families. “The United States government knows the location of all children in its custody and is working to reunite them with their families,” officials wrote on a DHS fact sheet released on Saturday night.

The Trump administration is saying that most of the family reunifications are taking place at the Port Isabel Service Processing Center in Texas, but attorneys and advocates describe the facility as a jail.

As Vox’s Dara Lind wrote:

The Trump administration is now promising to streamline this process. According to Saturday’s fact sheet, parents separated from their children will be held in a single immigration detention facility, where staff will coordinate with HHS to make sure parents are put in touch with their children (at least, if HHS feels there’s enough information to prove the parent really is related to the child) and allowed to speak to them at least twice a week.

But advocates and lawyers say it’s still unclear how well the streamlined process is working — especially since the Trump administration didn’t have a reunification process set up before it started separating families. And the fact that two different agencies are in charge of adults and children makes everything more complex.

Detained parents are forced to make terrible choices

ICE has a publicly available locator of adults detained by the agency, but if a parent has been released or deported, it is much more difficult to find his or her location. Meanwhile, ORR has set up a national call center for attorneys and parents trying to find children still in the custody of ORR.

Again, if a child has been released or deported, locating the younger is incredibly difficult. Finding extremely young children can prove even more challenging because some kids don’t speak English or are simply too young to speak.

The Texas Civil Rights project has confirmed that two children that are siblings have been deported back to their home country without their parents. The group is working to determine if more children — or parents — have also been deported without being reunified.

There are stories circulating of parents being given a slip of paper with a 1-800 number on it but not being told which facilities, or even which states, their children are being detained in. This weekend, the Texas Tribune reported claims from one adult migrant and two immigration attorneys that parents were being told they could reunify with their kids at the airport if they agreed to voluntary deportation.

Again, as Lind wrote:

What this means, in practice, is that a parent who is currently trying to pursue an asylum claim but wants to see her child as quickly as possible will have to waive two sets of rights: her own and her child’s. She’ll have to withdraw her own asylum case and agree to be deported instead. And she’ll have to agree that her child should withdraw their own case to remain in the US — which is a separate case in the legal system because the child is now considered “unaccompanied” — in order to accompany her back to her home country.

The mothers in the Hutto Detention Center are desperate for answers about the whereabouts of their kids.

“There are many who are extremely distraught,” Carson said, adding one women sent an anonymous letter describing the feeling inside the detention facility.

“She describes mothers wailing in anguish, people fainting who can’t stand it,” Carson said. “It’s really strong — she says it’s one of the harshest things they could do, to take their kids away.”