File-In this Dec. 13, 2018, file photo, teen migrants walk in line inside the Tornillo detention camp in Tornillo, Texas. Government investigators say many more migrant children may have been separated from their parents than the Trump administration has acknowledged. (AP Photo/Andres Leighton, File)
File-In this Dec. 13, 2018, file photo, teen migrants walk in line inside the Tornillo detention camp in Tornillo, Texas. Government investigators say many more migrant children may have been separated from their parents than the Trump administration has acknowledged. (AP Photo/Andres Leighton, File)

Washington — The Trump administration separated thousands more migrant children from their parents at the U.S. border than previously has been made public, according to an investigative report released on Thursday, but the federal tracking system has been so poor that the precise number is hazy.

According to the report issued by the inspector general for the Department of Health and Human Services, the separated children include 118 taken between July and early November — after the administration halted a short-lived family separation policy that provoked a political firestorm and public outrage.

The report estimates that thousands of additional youngsters were taken into government custody from early in the Trump administration, months before the government announced it would separate parents and children in order to criminally prosecute their parents, through late last spring.

Previous administrations also separated minors from adults at the border in some instances, usually when they suspected the child was smuggled, or the parent appeared to be unfit. The latest report documents a sharp increase in separations under President Donald Trump.

Based on available records, separated children accounted for 0.3 percent of all unaccompanied minors taken into HHS custody in late 2016, near the end of the Obama administration. By August 2017, the percentage had increased more than tenfold, to 3.6 percent.

A large number of the separated children were released from federal custody before a court order last June that required federal officials to track carefully the status of some 2,500 separated children and submit regular updates on their status to a federal judge.

Immigration enforcement officials say their biggest reason for transferring youngsters into HHS custody is that their parents had criminal histories. But information on the parents’ criminal records often was so sketchy, the report said, that it is unclear whether the separations were warranted or whether the children could safely be returned to their parents.