Around a dozen documents with classified markings were found at former Vice President Mike Pence's Indiana home on Jan. 16, according to a letter sent to the National Archives by Pence's lawyer.

Pence's team notified the National Archives on Wednesday that a small number of documents were "inadvertently boxed and transported" to the former vice president's home at the end of the Trump administration. Pence was "unaware of the existence of sensitive or classified documents at his personal residence," wrote Greg Jacob, Pence's representative for dealing with records related to the presidency, to the Archives.

The documents were collected by the FBI at Pence's home in Carmel, Indiana, on Thursday evening. Pence was in Washington, D.C., for the annual March for Life when the FBI collected the documents.

It is not yet clear what the documents are related to or their level of sensitivity or classification.

Pence asked his lawyer to conduct the search of his home out of an abundance of caution, and the attorney began going through four boxes stored at Pence's house last week, finding a small number of documents with classified markings, sources told CNN.

The findings at Pence's residence come as President Joe Biden faces mounting criticism and a federal investigation over the discovery of classified materials at his Delaware home, and an old office at a Washington, D.C., think tank.

Former President Donald Trump is also under federal investigation, stemming from the discovery of hundreds of documents with classified markings, as well as hundreds of pages of presidential records at his private Florida club and residence, Mar-a-Lago.

The FBI searched Mar-a-Lago with a search warrant in August, and following the event, Pence said that he had not personally retained any classified material upon leaving office. "No, not to my knowledge," he told the Associated Press in August.

Again in November, Pence was asked by ABC News whether he had taken any classified documents from the White House.

"I did not," Pence responded.

"Well, there'd be no reason to have classified documents, particularly if they were in an unprotected area," Pence continued. "But I will tell you that I believe there had to be many better ways to resolve that issue than executing a search warrant at the personal residence of a former President of the United States."

The news about Pence comes amid speculation that he is readying for a run at the Republican nomination for president in 2024.