A federal judge halted the Justice Department's review of materials seized from former President Donald Trump's Mar-a-Lago estate, describing a threat to institutions and the risk of media leaks that could cause harm to Trump.

In a ruling issued on Labor Day, the U.S District Court Judge said there was an "unquantifiable potential harm by way of improper disclosure of sensitive information to the public".

Cannon allowed a special master to review the seized materials for possible attorney-client and executive privilege. There is no precedent for a former executive to bar review of materials by a sitting executive branch when the government has determined the need is urgent.

The department will consider the next steps in the litigation.

Cannon gave the Justice Department and Trump's lawyers until September 9 to propose a list of special master candidates and outline their duties and limitations. Cannon decided that the documents wouldn't be returned to Trump.

According to the Justice Department, if Cannon were to make a ruling like this, she should stop the department from doing anything.

Cannon wrote that the appointment of a special master wouldn't impede the intelligence community's assessment of whether Trump's possession of top- secret documents caused harm to U.S. national security. The Office of the Director of National Intelligence is leading the review.

The FBI is a member of the intelligence community and could be involved in the ODNI assessment. A spokesman for ODNI wouldn't comment on Cannon's ruling.

The assessment of the potential risk to national security that would result from the disclosure of the relevant documents was described by the director of national intelligence. She promised that the review of the documents that were seized from Trump's Florida estate wouldn't interfere with the criminal investigation. Cannon's order may affect that review.

The ruling was based on Trump's claims of potential harm. Medical documents, correspondence related to taxes, and accounting information were some of the items seized by the Justice Department'sfilter team.

Cannon said that leaks to the media of information related to the seized materials could pose a risk to Trump.

The former president's residence was searched in extraordinary circumstances.

She wrote that the stigma associated with the subject seizure is in a league of its own. Any degree of property that should be returned would result in a different order of harm.

Cannon said that investigators had flagged potentially privileged material that was not screened by the filter team.

These flags were actually examples of the filter process working.

Cannon wrote that the court wasn't so sure. The integrity of the members of the Investigative Team is demonstrated by these instances. The Privilege Review Team failed to find potentially privileged material on more than one occasion.

Cannon rejected the government's contention that Trump could never be able to block the department's review of the materials because of Nixon-era case law.

She wrote that the Supreme Court did not rule out the possibility of a former President defeating an incumbent President.

Cannon said that Trump did not assert executive privilege over any of the materials taken from his home. When the Justice Department first expressed an interest in reviewing the classified material taken from his home, Trump decided against taking the matter to court.

When an attorney's office is raided or a phone is seized, special masters are usually appointed to prevent the disclosure of privileged information to investigators. Trump's home does not fit in with the traditional rubric. Cannon noted that courts have the power to appoint special masters.

Special masters are usually found in the more traditional setting of law firms and attorneys' offices. The Court doesn't see why these concerns wouldn't apply to the office of a former president.

A special master was ordered in the case of Project Veritas, whose leaders' phones were seized as part of an ongoing investigation. Cannon pointed out that a special master was appointed even though the search did not involve an attorney.