Five additional pages of classified material have been found at Joe Biden's family home in Delaware, the White House said Saturday in a new twist in a politically sensitive affair for the president.
It was the latest in a series of revelations about the apparently improper storage of papers dating from Biden's time as Barack Obama's vice president. Biden has said he had no intention of keeping any classified documents.
White House lawyer Richard Sauber said the latest papers were found after he visited the home Thursday to oversee the transfer to the Justice Department of a first batch of documents found a day earlier in a room next to the home's garage.
Biden's personal lawyers searching the garage at the home in Wilmington, Delaware – where the 80-year-old president often spends weekends – had found a document marked classified in the garage itself.
As these attorneys lacked the necessary security clearance to read it, they notified the Justice Department, Sauber said in a statement.
A 1978 law obliges US presidents and vice presidents to hand over their emails, letters and other official documents to the National Archives.
Sauber said he does have the necessary security clearance, so he then went to the Delaware house to check out the situation for himself. That is when he found the other five pages, he said.
He said all documents were "immediately and voluntarily" handed to the Justice Department.
Critics of Biden have seized on the steady series of revelations to argue that he has not been transparent and forthcoming.
Others papers had been found on November 2 at Biden's former office at a Washington think tank, where he had offices after leaving the Obama White House.
The president's attorneys had also found "a small number of documents," potentially confidential, on December 20 in the Wilmington garage, and alerted the Justice Department.
Amid rising furor over the discoveries in Washington, US Attorney General Merrick Garland on Thursday named Robert Hur as an independent prosecutor to investigate Biden's handling of classified documents.
The issue is an unwelcome distraction for Biden as he prepares to announce whether he will seek a second term.
The disclosures have prompted comparisons to the case of former president Donald Trump, who is also being investigated by a special counsel for storing hundreds of classified materials at his Mar-a-Lago estate in Florida and allegedly obstructing government efforts to retrieve them.
In contrast, Sauber emphasized that Biden had returned documents "immediately and voluntarily" when they turned up.
"I take classified documents and classified material seriously. We're cooperating fully (and) completely with the Justice Department's review," Biden told reporters Thursday.
"As part of that process, my lawyers reviewed other places where documents from my time as vice president were stored, and they finished the review last night."
The first cache of Biden documents was discovered in November, a week before last year's midterm elections, but only acknowledged by the White House on Monday, prompting accusations from Republicans that it was kept secret for political reasons.
Republicans, newly in control of the House of Representatives, have vowed to launch an inquiry to be headed by James Comer, a conservative from Kentucky who chairs an oversight committee.
"The Biden White House's secrecy in this matter is alarming. Equally alarming is the fact that Biden aides were combing through documents knowing there would be a Special Counsel appointed," Comer said in a statement.
"Many questions need to be answered but one thing is certain: oversight is coming," he said, condemning what he called "President Biden's three strikes against transparency."