FBI agents who searched former US president Donald Trump's Florida home seized 11 boxes of documents, including some marked 'top secret' and even more sensitive documents, according to court papers released Friday, and the government is investigating possible Espionage Act violations.

At the Justice Department's request, a US judge on Friday released an itemized list of items taken from the Mar-a-Lago estate on Monday along with the accompanying search warrant FBI agents used to gain access to the property.

According to the list, some documents were marked "sensitive compartmented information'', a special category meant to protect the most important secrets that if revealed publicly could cause "exceptionally grave'' danger to US interests.

In addition to four sets of top-secret documents, agents recovered three sets of secret documents and three sets of confidential documents, according to the list released by US Magistrate Judge Bruce Reinhart with the text of the warrant.

The list also shows agents collected other presidential records, including information about the "President of France'', a binder of photos, "miscellaneous secret documents'' and "miscellaneous confidential documents''.

The warrant lists alleged crimes under investigation: violations of the Espionage Act, which prohibits the unauthorized retention of national security information that could harm the US or aid a foreign adversary; a federal crime that makes it a crime to destroy or conceal a document in order to obstruct a government investigation and another statue associated with unlawful removal of government materials. Punishment and fines upon conviction are based on the number of concealed or destroyed documents.

In a post on Friday on his Truth Social network, Trump suggested without any evidence that any recovered nuclear documents were planted by the FBI during their search of his property on Monday.

In another post, he stated that the seized documents were "all declassified'' and said he would have turned them over to the Justice Department if asked. "They could have had it anytime they wanted without playing politics and breaking into Mar-a-Lago,'' he said.

Presidents do have authority to declassify documents, but officials have said that Trump hasn't demonstrated that he followed normal notification steps which help the National Security officials who know who is allowed to view what information, while in office. Now that he is out of office, Trump no longer has the authority to declassify documents.

Now that the government has possession of the materials, Trump has no say in how they are used, including against him in court. Some of the boxes removed could also be personally, politically or legally damaging.

"If there is something in there that can be evidence of another crime, that's fair game,'' said former federal prosecutor Neama Rahmani.

Trump also noted in that same post that former president Barack Obama kept 33 million pages of documents, including some that were classified. The National Archives said in a statement that the documents are housed by it for the Obama presidential library.

Attorney General Merrick Garland announced Thursday that the Justice Department would seek to unseal the search warrant, which he said he had authorized, and an itemized list of what had been removed from Trump's property. He did so after Trump disclosed the search and his lawyers told reporters details about what the FBI agents were looking for.

The judge gave the Justice Department until 3 pm Eastern time on Friday to confer with Trump's lawyers and tell the court whether Trump planned to contest the release of the warrant and itemized list. Trump then said on his Truth Social network that he supported unsealing the warrant.

Various media outlets reported Thursday that the Justice Department had already used subpoenas and "other less intrusive means'' to recover documents this spring but sought the search warrant because it believed Trump still had confidential or top-secret documents at Mar-a-Lago.

Under the Presidential Records Act of 1978, all presidential records are supposed to be turned over to the National Archives when a president leaves office. The Archives had already retrieved more than 15 boxes of material that had been improperly taken to Mar-a-Lago.

The FBI search of Trump's property sparked an outrage among Republicans, with Trump calling it a 'raid''. Trump's allies accused the Justice Department of a "witch hunt'', demanded it explain why it took place and some said Garland should be forced to resign.

Republican Ohio Representative Michael Turner said Friday that the release of the warrant and the itemized list of materials removed still left "unanswered questions''. "We are very concerned about the method that was used to raid Mar-a-Lago,'' he said, citing the length of the daylong search.