A US judge on Monday granted Donald Trump’s request for the appointment of a “special master” to independently review material seized in an FBI raid on his Florida home, dealing a blow to prosecutors.

Government attorneys had opposed Trump’s request, arguing that the appointment of a special master to screen for privileged material could harm national security, and was also unnecessary as a team had already completed a screening.

The decision could delay the investigation into Trump’s handling of classified materials and is a boost for the former president, who has denounced the August 8 raid as “one of the most egregious assaults on democracy in the history of our country,” and denied all wrongdoing.

Judge Aileen Cannon wrote in her order that “a special master shall be appointed to review the seized property, manage assertions of privilege and make recommendations thereon, and evaluate claims for return of property.”

The ruling — which temporarily blocks the government from reviewing or using materials seized in the raid — made an exception for “intelligence classification and national security assessments.”

The judge gave both sides until Friday to come up with a list of candidates for the role of special master.

Trump is facing mounting legal pressure, with the Department of Justice saying top secret documents were “likely concealed” to obstruct an FBI probe into Trump’s potential mishandling of classified materials.

When agents searched Trump’s Mar-a-Lago resort, they found material so sensitive that “even the FBI counterintelligence personnel and DOJ attorneys conducting the review required additional clearances before they were permitted to review certain documents,” a government court filing said.

‘Highly classified’

The FBI raid came after a review of “highly classified” records that Trump finally surrendered to authorities in January after months of back and forth with the National Archives and Records Administration.

The 15 boxes handed over by Trump were found to contain 184 documents marked as confidential, secret or top secret.

After prompting from the FBI, Trump’s lawyer eventually turned over an additional 38 classified documents — and provide “sworn certification” that they represented the last of the material.

But the FBI went on to uncover “multiple sources of evidence” showing classified documents remained at Mar-a-Lago.

Attorney General Merrick Garland said he personally approved the Mar-a-Lago raid, and the decision on whether Trump is charged with a crime ultimately rests with him.

Bill Barr, who held the same post during Trump’s presidency, has said the government appeared justified in raiding Trump’s home, and that he suspected authorities have “good” evidence of obstruction.

In addition to the documents probe, Trump faces investigations in New York into his business practices, as well as legal scrutiny over his efforts to overturn results of the 2020 election, and for the January 6, 2021 attack on the US Capitol by his supporters.

Trump was impeached for a historic second time by the House of Representatives after the Capitol riot — he was charged with inciting an insurrection — but was acquitted by the Senate.