Former U.S. President Donald Trump's team may not have returned all the classified documents seized from the White House at the end of his presidency, even after an FBI search of his home. The U.S. Attorney's Office announced this, calling it a potential threat to national security that needs to be investigated, Reuters reports.

Trump is under investigation for keeping government documents, some marked classified, at a resort in Palm Beach, Florida after leaving office in January 2021.

Those 100 documents represent only a fraction of the more than 11,000 documents and photos seized, most of which the current administration says Trump can view because they are not classified.

The prosecutor's office also asked the judge to keep an independent arbiter, called a "special master," from reviewing the classified materials seized from the Trump residence.

Trump, in a post on his Truth Social platform, called the request a waste of money.

The Justice Department speculated that Trump may have taken other classified records from the White House that investigators have yet to discover. Earlier, the Justice Department released a detailed list of property seized from Trump's home that showed the FBI found 48 empty folders marked as classified and another 42 that said they should be returned to the secretary of staff or military aide.

Prohibiting the use of classified records in a criminal investigation could impede efforts to identify the existence of any additional classified records that are not properly maintained, which in itself poses a potential threat to national security, the prosecutor's office said.

The prosecutor's office has asked a judge to rule on the matter on Sept. 15. If she denies their request, they intend to appeal to the 11th U.S. Circuit Court of Appeals in Atlanta, where six of the 11 sitting judges are Trump appointees.

The Justice Department is also investigating possible obstruction of justice after finding evidence that documents may have been removed or withheld from the FBI.