The federal government has released details on the whereabouts of some 2,500 immigrant children who were separated from their parents in the wake of President Donald Trump’s “zero tolerance” immigration policy that criminally prosecutes immigrant parents when they cross the border.

The Department of Homeland Security (DHS) on Saturday released a fact sheet announcing its “well coordinated” effort to reunited parents with their children, who have been transferred to facilities across the country run by the Department of Health and Human Services (HHS).

DHS says that 522 children have been reunited with their parents since last week when Trump, in the face of a firestorm of bi-partisan criticism, signed an executive order ending his administration’s family separation policy

The agency said that 2,053 children remain in its custody, and that it is “working with relevant agency partners to foster communications and work towards reuniting every minor and every parent or guardian via well-established reunification processes.” Those “agency partners” are Immigration and Customs Enforcement (ICE), the Office of Refugee Resettlement (ORR) and Customs and Border Protection (CBP), which has recently faced charges of rampant abuse and neglect of unaccompanied immigrant children in its custody. 

But the dubious language of Trump’s executive order could be exploited by the federal government to continue separating families in various circumstance, according to legal experts.

The executive order, signed on June 20, calls on families to be detained together, but separations would be permitted if a parent poses “a risk to the child’s welfare.” 

Despite the executive order, the American Civil Liberties Union said it would move ahead with its lawsuit contesting family separations. In March, the ACLU filed a suit on behalf of a Congolese mother seeking asylum who had been separated from her 7-year-old daughter upon entering the U.S. The rights group argues the government’s family separation policy violates due-process rights granted by the 5th Amendment.   

Meanwhile, efforts to reunite children with parents promises to be arduous. Children are in detention centers across the country, from California to New York. And lawyers helping parents locate their children describe a frenzied, frustrated search with little help from the government.

“Either the government wasn’t thinking at all about how they were going to put these families back together, or they decided they just didn’t care,” Natalia Cornelio, with Texas Civil Rights Project, told The Washington Post. The rights group represents 300 detained parents but has only located two children.

On Saturday, dozens of Democrats traveled to McAllen, Texas, to visit a detention center near the Mexico border, where unaccompanied children are held in 30-by-30-foot cages in a 77,000 square-foot facility. 

“People fleeing violence and seeking refuge in the United States are being treated like criminals,” said Rep. Barbara Lee (D-Calif.). “Parents don’t know where their children are. Children are crying out for their parents. This is a violation of human rights.”