CBS News has learned that more documents marked classified from Joe Biden's tenure as vice president were found in at least one additional location than previously known. The discovery was made after lawyers for Mr. Biden found the first batch of roughly 10 documents at a private office in Washington, D.C., on Nov. 2.
It is not clear when the additional documents with classified markings were found.
A source familiar with the Justice Department's review did not identify the additional location where documents were found. The U.S. attorney charged with investigating the Biden documents is aware of the additional documents, but sources couldn't say where these documents are being housed.
The White House did not respond to a request for comment. Lawyers designated by Mr. Biden to handle his post-vice presidency papers did not respond to multiple phone calls.
NBC News first reported that additional Biden documents with classified markings were found at another location.
On Monday, a White House lawyer confirmed that personal lawyers for the president had found documents marked classified at the Penn Biden Center and immediately turned them over to the National Archives. But that lawyer, Richard Sauber, did not acknowledge in his statement classified material had been discovered in a second location.
Officials are looking at the possibility that other documents may be in other locations.
"Since that discovery [on Nov. 2], the President's personal attorneys have cooperated with the Archives and the Department of Justice in a process to ensure that any Obama-Biden Administration records are appropriately in the possession of the Archives," Sauber wrote Monday.
President Biden said on Tuesday he was "surprised" that government documents had been found at an office he used periodically between 2017 and 2019. Sources told CBS News the material included briefings, some bearing highly classified markings.
The revelations about the Biden documents occur as the Justice Department continues to review former President Donald Trump's presidential records. In August, the FBI executed a search warrant at Mar-a-Lago that yielded more than 100 documents marked classified.
That search followed repeated efforts by the Archives and the Justice Department to retrieve what the government considered to be sensitive documents from Trump's personal residence that were required to have been turned over to the Archives under the law.