The recovery of the boxes from Trump's Florida resort raises new concerns about his adherence to the Presidential Records Act, which requires the preservation of memos, letters, notes, emails, faxes and other written communications related to a president's official duties.

Trump advisers deny any nefarious intent and said the boxes contained mementos, gifts, letters from world leaders and other correspondence. The items included correspondence with North Korean leader Kim Jong Un, which Trump once described as "love letters," as well as a letter left for his successor by President Barack Obama, according to two people familiar with the contents.

Archives officials confirmed the transfer, which occurred in mid-January, following publication of a version of this story by The Washington Post earlier Monday. The agency said in a statement that "these records should have been transferred to NARA from the White House at the end of the Trump Administration in January 2021," and that Trump representatives are "continuing to search" for additional records.

"The Presidential Records Act is critical to our democracy, in which the government is held accountable by the people," Archivist of the United States David Ferriero said in the statement. "Whether through the creation of adequate and proper documentation, sound records management practices, the preservation of records, or the timely transfer of them to the National Archives at the end of an Administration, there should be no question as to need for both diligence and vigilance. Records matter."

Discussions between the Archives and the former president's lawyers that began last year resulted in the transfer of the records in January. One person familiar with the materials said Trump advisers discussed what had to be returned in December. Some of the people familiar with the transfer spoke on the condition of anonymity to reveal internal details.