The United States Justice Department has decided to appeal a judge’s order that temporarily blocked investigators from reviewing documents seized from Donald Trump’s home by FBI agents during a search last month.

In a court filing on Thursday, the department asked the judge to partially suspend — pending appeal — her decision to pause the review of classified documents taken from the former president’s Mar-a-Lago estate and the appointment of an independent arbiter to vet the material.

Judge Aileen Cannon had ruled earlier this week in favour of appointing a so-called “special master” to assess all the documents for content that falls under attorney-client or executive privilege.

Justice Department lawyers wrote that although they disagree with Cannon’s decision to temporarily block the review of materials seized in the August 8 search, they are only looking to suspend the ruling when it comes to classified records.

They said they would turn to an appeals court to secure the suspension of the order if Cannon does not grant the stay by September 15.

They argued that stopping the review of classified documents “will cause the most immediate and serious harms” to the US government and public.

“The classified records – a discrete set of just over 100 documents – have already been segregated from the other seized records and are being maintained separately,” the Justice Department wrote in a filing to Cannon, a Trump appointee.

Department lawyers said Cannon should grant the stay because the appeal is likely to succeed, and resuming the review of those documents would not cause harm to Trump.

“The government and the public are irreparably injured when a criminal investigation of matters involving risks to national security is enjoined,” they wrote.

Cannon had allowed an intelligence community assessment of the material for national security risk to proceed.

The Justice Department’s appeal comes a day before a judge-ordered deadline for the parties to submit candidates for the special master role.

The Justice Department had pushed back against Trump’s demand for a special master, saying that it had already gone through the materials and identified a “limited” number of potentially privileged documents.

The department is conducting a criminal investigation into Trump’s possible mishandling of classified documents.

Many legal scholars had criticised Cannon’s decision to appoint a special master, saying that it has no legal basis and that it would only serve to slow down the investigation.

Michael Meltsner, a law professor at Northeastern University in Boston, said earlier this week that an appeal of the judge’s ruling would likely succeed but also carries risks.

“The opinion by this judge is totally inconsistent with the law. It would not surprise me if an appellate court – if it ever gets the issue – would reverse her very quickly,” he told Al Jazeera.

“But appeals may take time, appeals may distract, and appeals may even find similar Trump-appointed judges in the Court of Appeals. And if the Court of Appeals rules against Trump, then they’ll go to the Supreme Court, and who knows what happens there.”

Trump and his allies have dismissed the investigation, saying without evidence that it is politically motivated.

President Joe Biden has denied having prior knowledge of the search and insisted that the White House does not interfere in Justice Department-led investigations.