A federal judge has temporarily halted deportations of families recently reunited after they were separated by the Trump administration.

The American Civil Liberties Union (ACLU) filed paperwork saying attorneys were concerned about “mass deportations” following the reunification of children aged five to 17 with their parents. They asked that deportations be stalled at least a week after the families were reunified, to allow time to ensure no family was being improperly deported.

Judge Dana Sabraw said on Monday he would order a halt to any deportations for a week until the government can respond to the ACLU motion. He asked if there were any issues over whether he had jurisdiction but there were no verbal objections.

He gave government lawyers one week to respond to the ACLU’s concerns, until 9pm on 23 July, and said he would rule permanently after going over the paperwork.

The Trump administration has said it completed reunifying all eligible children under five and is reunifying families with older children on a rolling basis.

The ACLU said in a court filing on Monday that its request was a response to “persistent and increasing rumors … that mass deportations may be carried out imminently and immediately upon reunification”.

Sabraw said late on Friday he was having second thoughts about whether the government was acting in good faith. He was responding to an administration plan to reunite more than 2,500 children aged five and older by 26 July.

The administration plan uses “truncated” procedures to verify parentage and perform background checks, excluding DNA testing and other steps taken to reunify children under five. The administration said the abbreviated vetting puts children at significant safety risk but is needed to meet the deadline.

On Friday, Sabraw said the government was presenting a “parade of horribles” that misrepresented his orders. He insisted the deadline be met.

“The task is laborious but can be accomplished in the time and manner prescribed,” he wrote in a subsequent order.

Sabraw scheduled four hearings to ensure compliance with his order.

Evelyn Stauffer, a spokeswoman for the Department of Health and Human Services, said on Saturday the administration proposed its plan “in the interests of transparency and cooperation” after concluding abbreviated vetting was necessary to make the deadline.

“Within the time the court allows, we will strive to implement the most comprehensive procedures possible to ensure child welfare,” she said. “We look forward to continuing our close work with the court to accomplish the goals we share of safe, expeditious reunification.”