SAN DIEGO >> The Trump administration asked a judge Friday for more time to reunite families who were separated at the border under its “zero-tolerance” policy to prosecute every person who enters the country illegally.

Hours before a hearing in San Diego, the Justice Department filed papers seeking an extension of the deadline, which is July 10 for all parents with children under 5 and July 26 to reunite everyone else.

The administration says federal law requires it to ensure that children are safe and that requires more time. Administration officials also say that they won’t be able to confirm a child’s parentage by the deadline if DNA testing is inconclusive. They will need more time to collect DNA samples or other evidence from parents who have been released from government custody.

U.S. District Judge Dana Sabraw, who was appointed by President George W. Bush, set the deadline last week, writing that the “situation has reached a crisis level” and that the “chaotic circumstances” were of the government’s own making. He scheduled Friday’s hearing for an update on compliance with his order.

More than 2,000 children were separated from their parents after Attorney General Jeff Sessions announced in May that the zero tolerance was in full effect, even if it meant splitting families. While parents were criminally prosecuted, children were placed in custody of the Health and Human Services Department. Trump reversed course on June 20 amid an international outcry, saying families should remain together.

On Thursday, Health and Human Services Secretary Alex Azar said less than 3,000 children are believed to have been separated, but that includes kids who may have lost parents along the journey, not just parents who were detained at the border. None had been transferred to Immigration and Customs Enforcement to be reunited with their parents.

In the court papers, the government said it has identified 101 children under 5 years old who were separated and is the midst of identifying older children. About 40 parents of children in the under-5 age group are in Homeland Security custody and another nine are in the custody of the U.S. Marshals Service.

Jonathan White, a Health and Human Services official, filed a declaration with the court that gives what is perhaps the most detailed account yet of what the government is doing and the hurdles it faces. Its database has some information about the children’s parents but wasn’t designed to reunify families under the court’s deadline.

The department has manually reviewed the cases of all 11,800 children in its custody by working nights and weekends, White said. The results of that review are being validated.

DNA cheek swab tests on parent and child take nearly a week to complete, said White, who called the risk of placing children with adults who aren’t their parents “a real and significant child welfare concern.”

“The Government does not wish to unnecessarily delay reunifications or burden class members,” the Justice Department filing reads. “At the same time, however, the Government has a strong interest in ensuring that any release of a child from Government custody occurs in a manner that ensures the safety of that child.”

Sabraw’s order in the class-action lawsuit filed by the American Civil Liberties Union applies to all families who have been separated and includes a halt to any future separations.

The ACLU sued in March on behalf of a Congolese woman who was separated from her daughter for five months after seeking asylum at a San Diego border crossing and a Brazilian asylum-seeker who has been separated from her son since an arrest for illegal entry in August near the Texas-New Mexico border.

The Congolese woman, identified in court documents as Mrs. L, claimed asylum on Nov. 1, 2017, and four days later was separated from her daughter. The girl, then 6, was sent to a Chicago shelter contracted by Health and Human Services, while the mother was held at a San Diego immigration detention facility until March 6.

The administration says the Congolese woman had no documents and was unable to prove she was the girl’s mother when she claimed asylum. U.S. authorities confirmed through DNA testing on March 12 that the woman was the girl’s mother and the two were reunited.

The Brazilian woman, identified as Mrs. C, served nearly a month in jail after her Aug. 26, 2017, arrest for illegal entry near Santa Teresa, New Mexico, and then spent about six months in immigration detention. Her son was also sent to a Chicago shelter the two recently reunited.