Classified documents have been found at former vice president Mike Pence's home in Indiana, his lawyer has said.
The records "appear to be a small number of documents bearing classified markings that were inadvertently boxed and transported to the personal home of the former vice president at the end of the last administration," Mr Pence's lawyer, Greg Jacob, told the National Archives in a letter last week.
He said Mr Pence "was unaware of the existence of sensitive or classified documents at his personal residence" and he "understands the high importance of protecting sensitive and classified information and stands ready and willing to cooperate fully with the National Archives and any appropriate inquiry."
Mr Jacob said Mr Pence immediately secured the documents in a locked safe.
FBI agents went to Mr Pence's home to collect the classified documents, his representative said in a separate letter.
When Mr Pence was asked in August whether he had taken any classified information with him when he left office, he told the Associated Press: "No, not to my knowledge."
In an interview with Fox Business in January, he described a "very formal process" used by his office to handle classified information, as well as steps taken by his lawyers to ensure none were taken with him.
"Before we left the White House, the attorneys on my staff went through all the documents at both the White House and our offices there and at the vice president's residence to ensure that any documents that needed to be turned over to the National Archives, including classified documents, were turned over," he said.
"So we went through a very careful process in that regard."
Classified documents found at Trump and Biden's homes
It comes after top secret documents were uncovered during an FBI search of Donald Trump's Mar-a-Lago home in Florida.
The Justice Department said around 300 documents marked classified, including at the top-secret level, were taken from the estate.
Officials are working to determine whether Mr Trump or anyone else should be charged with illegal possession of those records or with trying to obstruct the months-long criminal investigation.
Classified documents were also found at US President Joe Biden's home in Delaware, relating to his time as vice president in the Obama administration.
Republicans have sought to compare the investigations into Mr Biden's and Mr Trump's handling of classified documents.
The White House, however, has previously said the two cases are different because Mr Biden's team has cooperated with the authorities and turned over documents, while Mr Trump resisted doing so until the FBI searched his home.