Washington (CNN) Since the Trump administration announced it would end its practice of separating families apprehended at the southern border last June under its "zero tolerance" immigration policy, at least 245 children have been separated from their parents, according to a new court filing.

Between late June 2018 and early February of this year, the administration identified 245 children who had been separated, though four of them are under additional review. The administration said the basis for the separation in the majority of cases was "criminality, prosecution, gang affiliation or other law enforcement purpose."

The court document is a status report in an ongoing family separation lawsuit. The court will hold a hearing Thursday.

The American Civil Liberties Union originally filed the case against the Trump administration last year on behalf of a Congolese woman, referred to as "Ms. L," who was seeking asylum in the US and was separated from her 7-year-old daughter. The case was later expanded to become a class-action lawsuit.

District Judge Dana Sabraw issued a preliminary injunction last June blocking most family separations at the US-Mexico border and ordering that those already separated be reunited.

Read More