Washington (CNN) The Trump administration has reunited at least 450 families separated at the border with children 5 and older, including almost 100 just overnight.

But there are still roughly 1,900 who need to be reunified or ruled ineligible by next Thursday, and a government attorney warned "some complicated issues" will pop up in the coming week.

Still, at a court hearing Friday afternoon, the judge who last month ordered the government to put back together the families it had separated at the border said he was very pleased with how things are going.

"I am just very impressed with the effort that is being made," US District Judge Dana Sabraw told the attorneys in the case. "It really does appear that there's been great progress and that -- at least for those class members who are eligible and easy, relatively speaking, to reunify, and that's a very significant number of the group -- that that is happening, and it's very promising."

After the Trump administration's widely criticized "zero-tolerance" immigration policy that resulted in thousands of family separations at the border, Sabraw ordered the government to reunite families it had separated, including those from before that official policy.

Read More