National Archives asks former presidents and vice presidents to check for outstanding classified material

The National Archives has asked the offices of recent former presidents and vice presidents to review personal documents for any outstanding classified material or presidential records that have not been properly returned to the U.S. government, according to a letter obtained Thursday by ABC News.

The communication specifically refers to any material thought to be personal that might "inadvertently" contain presidential records, adding that "the responsibility to comply with the [Presidential Records Act] does not diminish after the end of an administration."

Sent via e-mail to the various offices, the letter opens by stating, "There have been several instances reported in the media where records containing classified information and subject to the Presidential Record Act (PRA) have been identified outside the physical custody of the National Archives and Records Administration (NARA). While much of the attention around these instances has focused on classified information, the PRA requires that all Presidential records of every Administration from Reagan onward must be transferred to NARA, regardless of classification status."

The National Archives declined to comment to ABC News on the letter, which was first reported by CNN.

ABC News has reached out to the offices that received the letter for a response. A spokesman for former President Barack Obama said all of Obama's classified records were submitted to the National Archives, "consistent with the Presidential Records Act." A spokesman for George W. Bush provided a similar statement, saying they "remain confident that no such materials are in our possession."

The National Archives sent letters to the offices of presidents dating back to the late Ronald Reagan. Former President Jimmy Carter, who turned 98 last October, and his administration are not subject to the request because the Presidential Records Act did not go into effect until January 1981.

The letter comes as classified documents have been found in the home of former Vice President Mike Pence and turned over to the FBI for review.

The revelation made Pence the third high-profile official to have classified material discovered at their residence in recent months, after President Joe Biden and former President Donald Trump, both of whom are now being investigated by special counsels under the Department of Justice.

Trump's Mar-a-Lago estate was searched by federal agents in August after what the federal government said was a monthslong effort to retrieve documents that Trump resisted handing over.

Trump has denied wrongdoing and asserted, without evidence, that he declassified the documents.