Classified documents have been found in an office used by Joe Biden while he was a private citizen.
The documents with classified markings from the Obama Administration were found as the Washington DC office was closed.
Under US law, all government documents must be handed over to the National Archives once a person leaves office.
The Department of Justice (DOJ) is now investigating the matter.
"The White House is cooperating with the National Archives and the Department of Justice regarding the discovery of what appear to be Obama-Biden Administration records, including a small number of documents with classified markings," White House lawyer Richard Sauber said.
"The documents were discovered when the President's personal attorneys were packing files housed in a locked closet to prepare to vacate office space."
Sauber said the White House notified the National Archives the day they were discovered in November.
The Archives took possession the following morning.
Biden was using the office in his capacity as an honorary professor of the University of Pennsylvania from 2017.
He had moved into the office after leaving the vice presidency that year.
Details of the classified documents have not been revealed, but fewer than half a dozen were reportedly found.
The discovery comes as former president Donald Trump faces potential criminal charges for not returning government documents after leaving office.
Trump's lawyers had claimed all had been returned to the National Archives, but a raid by the FBI on his country club Mar-a-Lago found dozens of classified documents.
Former US attorney and law professor Barb McQuade said there were distinguishing factors between the two cases.
"DOJ prosecutes mishandling of classified documents cases when there is an aggravating favour present," she said.
"Those factors are obstruction of justice, storage in a way that risks exposure, wilful violation, and disloyalty to (the) United States.
"In the Mar-a-Lago case, all but that last factor appear to be present.
"In the case of the Biden documents, there is no indication that any of the factors are met."
McQuade concluded the discovery was "not a big deal".
But Trump thought differently.
"When is the FBI going to raid the many homes of Joe Biden, perhaps even the White House?" the former president said
"These documents were definitely not declassified."
Biden is yet to comment on the documents found in his office.