Court documents have revealed the FBI seized 11 sets of classified information from Donald Trump's Florida property earlier this week, including some marked "top secret".
A federal judge has unsealed the search warrant and a list of the items recovered by the FBI after the former president said he did not object to their release.
The search warrant reveals Mr Trump is being investigated for possible violations of the Espionage Act, a federal law that prohibits the possession or transmission of national defence information.
The two other laws cited involve concealing, removing or destroying records.
In a statement on his social media platform, Mr Trump said the records at issue were "all declassified" and placed in "secure storage".
"They didn't need to 'seize' anything. They could have had it anytime they wanted without playing politics and breaking into Mar-a-Lago," he said.
Mr Trump had earlier called for the "immediate" release of the federal warrant the FBI used to search his Mar-a-Lago estate.
It came hours after the Justice Department had asked a court to unseal the warrant, with Attorney-General Merrick Garland citing the "substantial public interest in this matter".
In messages posted on his Truth Social platform, Mr Trump wrote: "Not only will I not oppose the release of documents … I am going a step further by ENCOURAGING the immediate release of those documents".
He continued to assail the FBI search of Mar-a-Lago as "unAmerican, unwarranted and unnecessary".
"Release the documents now!" he wrote.
The Justice Department's request is striking because such documents traditionally remain sealed during a pending investigation.
But the department appeared to recognise that its silence since the search had created a vacuum for bitter verbal attacks by Mr Trump and his allies, and that the public was entitled to hear the FBI's side about what prompted Monday's action at the former president's home.
"The public's clear and powerful interest in understanding what occurred under these circumstances weighs heavily in favour of unsealing," said a motion filed in federal court in Florida on Thursday.
During his successful 2016 presidential campaign, Mr Trump pointed frequently to an FBI investigation into his Democratic opponent, Hillary Clinton, over whether she mishandled classified information.
The department specifically requested the unsealing of the warrant as well as a property receipt listing the items that were seized, along with two unspecified attachments.
ABC/wires
