Roughly half of the children under 5 years old who were separated from their parents at the border will be back with their moms and dads by a court-imposed deadline Tuesday, but the Trump administration is still not sure when the rest will be reunified. Still, at a court hearing on Monday, the federal judge who set the deadline for reunifications said he was “very encouraged” thus far. “There’s no question that the parties are meeting and conferring,” District Judge Dana Sabraw said. “This is real progress and I’m optimistic that many of these families will be reunited tomorrow, and then we’ll have a very clear understanding as to who has not been reunited, why not, and what time-frame will be in place.” The hearing only covered the roughly 100 children under the age of 5 who were separated from their parents at the border. That group must be reunited by Tuesday under a deadline Sabraw set two weeks ago, when he first ordered the government to put the families back together. The government still has thousands more children aged 5 and older in its custody that it will have to reunite by July 26 – but the hearing did not cover that group. Attorneys for the government and the American Civil Liberties Union, which filed the original lawsuit challenging family separations, said they worked together intensely over the weekend to identify the families affected by the deadline and to work out how to move forward. Justice Department attorney Sarah Fabian provided the court with the most detailed data thus far on the 102 children under age 5 whom it identified as separated from their parents at the border. Of the 102: The ACLU, however, said it believes as many as 10 more children might not be on the government’s list, and said it would provide those names to the government to investigate. Fabian said the plan for Tuesday’s reunions was for the children to be released to Immigration and Customs and Enforcement, which runs the adult detention centers where their parents are being held. Once the children are handed over to their custody, ICE will release the families together. This plan bypasses the lengthy “sponsor” process that is required to release an unaccompanied immigrant child from Health and Human Services custody. Many parents have already been moved to detention facilities near their children in preparation, Fabian added. Outstanding questions Despite the progress over the weekend, a number of questions remained Monday. The ACLU is seeking clear deadlines to reunite the different groups of remaining children, though the judge deferred deciding on that until Tuesday, at the earliest. Sabraw asked ACLU attorney Lee Gelernt for his take on whether the administration is “in full compliance to the extent it can be” with the court’s deadline. “Let me put it this way: I think the government in the last 48 hours … has taken significant steps,” Gelernt said. But Gelernt took issue with the administration’s “continued insistence on using the longer reunification process” – procedures HHS uses for children who arrive to the US alone. That process requires lengthy background checks for potential sponsors, including parents. “I think the other point is, we just don’t know how much effort the government has made to find released parents,” Gelernt said. “They certainly haven’t reunited all the kids and parents who are noncriminals and don’t fall out of the class.” The hearing also barely touched on the more than 2,000 children still in government custody who will need to be reunited in coming weeks. The attorneys and judge did say, though, that they hoped the work that had gone into identifying the children under 5 and what is needed to reunite them with parents will help when it comes to the older group. The judge ordered the attorneys to file more thoughts by Monday evening on the timelines and procedures for reuniting those parents who will not rejoin their children Tuesday, and the court will hold another hearing Tuesday morning to discuss the issue further. CORRECTION: This story has been corrected to reflect that the children separated from their families affected by Tuesday’s deadline does not solely include children affected by the Trump administration’s “zero-tolerance” policy.