Documents like the kind found at Mar-a-Lago require a type of security clearance that sometimes only a couple dozen people have, and often only on a need-to-know basis

• Classified documents found at Mar-a-lago required special clearances due to their highly sensitive contents.
• Documents about highly classified operations were supposed to be kept under lock and key.

Classified documents like those found at former President Donald Trump's Mar-a-Lago home sometimes describe operations so sensitive that as few as a couple dozen people are allowed to view them, and are often only granted clearance on a need-to-know basis, according to a new report from The Washington Post.

On Tuesday, the news outlet revealed that highly confidential details about a foreign government's nuclear capabilities were among some of the documents seized by the FBI last month.

According to The Post, which cited several unnamed sources familiar with the search, documents about highly classified operations are supposed to be kept under lock and key and often in a secure facility. Documents are sometimes assigned an officer to monitor their whereabouts.

On August 8, federal agents searched Trump's home and discovered more than 10,000 government documents, according to a publicly released inventory. The Department of Justice is investigating whether Trump broke three federal laws, including the Espionage Act.

Insider's Tom Porter reported the investigations appear to be moving toward criminal charges for Trump, according to a former top counterintelligence official.

On Monday, a federal judge in Florida approved Trump's request for a court-appointed third party to review the files that were seized from the estate.

Representatives for Trump, The White House, and the Office of the Director of National Intelligence did not immediately respond to Insider's request for comment.