The Trump administration has conceded it separated 1,556 immigrant parents and children more than it had previously admitted in court, bringing the total count of families separated to almost 5,500.

The government had originally admitted to separating about 2,800 families when a California federal court ordered it to end the practice in June 2018 as part of a lawsuit brought by the ACLU.

But it has since identified more separations; approximately 1,090 occurred after and in violation of the court order. The additional 1,556 separations disclosed on Thursday, which included 207 children under the age of 5, happened before the Trump administration implemented its “zero tolerance” policy aimed at prosecuting anyone who crosses the border without authorization. Officials have cited the zero tolerance policy as the cause of family separations.

This latest count is apparently exhaustive. Over the course of the last six months, the government investigated each one of the 33,000 children who had been in the custody of the Department of Health and Human Services’ Office of Refugee Resettlement dating back to July 1, 2017, to determine the new tally of separations, Lee Gelernt, an attorney for the ACLU, said in an interview. But the ACLU is also currently investigating potential separations that could have occurred before July 1, 2017, he added.

“If we hear about separations that occurred in the first six months after inauguration, then we’re going to go back to court and ask for those,” he said.

The new tally comes after a Department of Homeland Security Office of Inspector General report published in January found many separated families had gone unidentified.

The OIG report said that the “lack of an existing, integrated data system” at DHS and HHS made it difficult to ascertain just how many families had been separated. The final list of separated families was consistently revised through December 2018. Now even more separations have come to light.

“It is shocking that 1,556 more families — including babies and toddlers — join the thousands of others already torn apart by this inhumane and illegal policy,” Gelernt said in a statement. “Families have suffered tremendously, and some may never recover. The gravity of this situation cannot be overstated.”

The “zero tolerance” policy led to family separations

The separations were a result of the Trump administration’s “zero tolerance policy.” Announced in April 2018, the zero tolerance policy coincided with a shift in the demographics of migrants showing up at the border: families now make up the majority of those apprehended, rather than single adult males.

The Trump administration has sent record numbers of asylum-seeking families to immigration detention. The government’s rationale was that the practice of releasing families while they awaited their court dates — formerly the typical practice, which Trump has called “catch and release” — was encouraging migrants to come to the US, and that keeping them in detention while their immigration cases were underway would deter further migration.

But the US does not have the infrastructure to detain families on the scale the Trump administration has sought. There are only three facilities nationwide licensed to hold families long-term: Berks Family Residential Center in Berks County, Pennsylvania; Karnes Residential Center in Karnes City, Texas; and South Texas Family Residential Center in Dilley, Texas.

The government also can’t hold children in adult detention facilities for longer than 20 days under the Flores settlement agreement, which came from a 1997 court case in California. After the 20-day mark, children have to be transferred to the Department of Health and Human Services or another facility licensed to administer their care.

Trump officials have repeatedly cited these restrictions on the detention of immigrant children as the reason why they started separating families after former DHS Secretary Kirstjen Nielsen signed a memo in April 2018 greenlighting the practice. Even after leaving office, Nielsen has continued to defend her testimony before Congress that December that the administration “never had a policy for family separation” and that the administration was merely enforcing immigration laws.

Officials have also said the practice wasn’t anything new. To an extent, that’s true — President Barack Obama also separated some families. But the number of separations that occurred under the Obama administration did not even come close to the number that have occurred under Trump, and it wasn’t done under an official policy.

Amid public backlash against family separations, Trump issued an executive order purporting to put a stop to them in June 2018. The California court also blocked the policy that month and ordered the government to reunify the families.