Updated

President Biden aides have found at least one more batch of classified documents located at a location other than the Penn Biden Center office in Washington, D.C., that he used in the years after he was vice president during the Obama administration, Fox News has confirmed.

A source told NBC News, which first reported the development, that aides to Biden have been searching for additional documents that contained classified material in other locations that may have been used by the president.

The development comes after a separate batch of classified documents were recovered from Biden's private office located at the Penn Biden Center in November.

While at the North American Leaders' Summit in Mexico City on Tuesday, Biden addressed the documents recovered from the Penn Biden Center.

BIDEN 'SURPRISED' TO LEARN OF CLASSIFIED DOCS AT PENN THINK TANK: 'I DON'T KNOW' WHAT'S IN THEM

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President Biden walks over to talk with reporters before he and first lady Jill Biden board Marine One on the South Lawn of the White House in Washington, D.C., on Wednesday. (AP Photo/Susan Walsh)

"Let me get rid of the easy one first," Biden said. "People know I take classified documents and classified information seriously."

"They did what they should have done. They immediately called the [National Archives]… turned them over to the Archives, and I was briefed about this discovery and surprised to learn that there were any government records that were taken there to that office," Biden added. "But I don't know what's in the documents. My lawyers have not suggested I ask what documents they were."

When asked during Wednesday's press briefing if Biden has asked his lawyers to look into whether any other classified documents were taken to other locations, White House press secretary Karine Jean-Pierre declined to share any further information.

MCCARTHY REACTS TO CLASSIFIED DOCUMENTS DISCOVERED FROM BIDEN'S TIME AS VP: DEMS 'OVERPLAYED THEIR HAND'

Joe Biden and Amy Gutmann

Vice president Joe Biden launches his "Moon Shot" mission to cure cancer with a tour of the University of Pennsylvania's Abramson Cancer Center and a roundtable conversation with researchers there on Jan. 15, 2016. (Ed Hille/Philadelphia Inquirer/Tribune News Service via Getty Images)

"I'm just not going to speak to this. I'm going to let the process continue. It's an ongoing process. And so I'm just not going to speak to this from here. It is more prudent and more appropriate for my colleagues at the White House Counsel," Jean-Pierre said.

The documents found at the Penn Biden Center originate from Biden's tenure as vice president and were found on Nov. 2, said Richard Sauber, special counsel to the White House.

"The documents were not the subject of any previous request or inquiry by the archives," Sauber said.

"Since that discovery, the President's personal attorneys have cooperated with the Archives and the Department of Justice in the process to ensure that any Obama-Biden Administration records are appropriately in the possession of the Archives," he added.

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President Biden speaks during a ceremony at the White House marking the two-year anniversary of the Jan. 6, 2021, insurrection at the U.S. Capitol in Washington, D.C., on Friday. (Ting Shen/Bloomberg via Getty Images)

U.S. Attorney for the Northern District of Illinois John Lausch, an appointee of former President Donald Trump, was selected to review the issue by Attorney General Merrick Garland.

The Justice Department and FBI both declined to comment.

Fox News' Paul Best contributed to this report.