Two of the 2,814 immigrant children who were separated from their parents during the Trump administration's implementation of the "zero tolerance" policy last spring remain in federal custody because they could not be reunified, according to a senior Health and Human Services official.

Commander Jonathan White of the HHS Office of Assistant Secretary for Preparedness and Response, said 2,160 of the 2,814 children that a federal judge had ordered be reunited with family members are with a parent as of Tuesday morning.

Exactly 595 children were released from HHS Office of Refugee Resettlement through "appropriate discharges," White testified before the Senate Homeland Security and Governmental Affairs Committee Tuesday. Most of those kids were sent to family members, he said.

Sixteen children were not eligible to be reunited with parents, though the whereabouts of those children remains unclear.

Thirty-two children have remained in ORR care since at least last June because their parents "waived reunification" as a result of consulting with the suing party, the American Civil Liberties Union, White said.

Nine others who were grouped in the 2,814 figure were deemed to have arrived at the U.S.-Mexico border alone, without a parent, despite initially being counted as part of a family.

Finally, two children are pending reunification.

"We can't reunify them at this time until the parent conveys their wishes to the ACLU," said White.

The children were taken away from the adults they arrived at the southern border with from last April through half of June as a result of a Justice Department directive for Customs and Border Protection to refer all adults for prosecution. Then-Attorney General Jeff Sessions said the White House had "zero tolerance" for trespassers and split the families in order to prosecute the adults.

Illegal entry is a misdemeanor on the first offense and a felony thereafter.

The ACLU sued Immigration and Customs Enforcement, which is where families who have been taken into CBP custody are transferred. ICE can legally hold families for up to 20 days before they must release people into the country, at which point they are told to appear for their asylum hearing sometimes months or years later.

Last summer, the ACLU expanded a court case involving a woman, referred to as Ms. L, who had been separated from her daughter years earlier to a class-action lawsuit. Dana Sabraw, a judge for the Southern District of California, had ordered all children be reunited with guardians.

A recent HHS inspector general report stated thousands more children were separated from their parents during the two-month-long policy implementation last year.