John Bolton says Trump's claim he declassified documents before taking them to Mar-a-Lago is 'almost certainly a lie'

• Trump claimed he had declassified classified documents that the FBI found at Mar-a-Lago.
• John Bolton told The New York Times he believes the former president is lying.

Former President Donald Trump's claim that he declassified documents before taking them to Mar-a-Lago is "almost certainly a lie," his former national security adviser told The New York Times.

"I was never briefed on any such order, procedure, policy when I came in," John Bolton told the Times. "If he were to say something like that, you would have to memorialize that, so that people would know it existed."

Bolton said he had never heard of such an order the entire time he was working for Trump or after he was fired from the administration.

"When somebody begins to concoct lies like this, it shows a real level of desperation," Bolton told the Times.

The FBI found 11 sets of classified documents, including some that were marked top-secret, in the August 8 raid on Mar-a-Lago.

In the days after the raid, Trump tried to defend the documents by claiming he had a "standing order" to declassify documents "the moment" they left the Oval Office. But experts have said there's a formal procedure for declassifying documents, and it's unclear if Trump ever followed it.

"He can't just wave a wand and say it's declassified," Richard Immerman, a historian and an assistant deputy director of national intelligence in the Obama administration, told NBC News. "There has to be a formal process. That's the only way the system can work."

The possible crimes the Department of Justice is investigating don't have to do with the classification of the documents. Investigators are looking at whether Trump broke three laws — one relates to removing information about the US's national defense, and the other two relate to the concealment or destruction of government records.