US President Joe Biden's counsel said on Saturday that five additional pages with classified markings were discovered at the president's Wilmington, Delaware home on Thursday, and they were immediately handed to Justice Department officials.
Mr Biden's special counsel, Richard Sauber, said he traveled to Biden's Wilmington home on Thursday to facilitate the handover to the Justice Department of a document with classified markings that was found there earlier.
"While I was transferring it to the DOJ officials who accompanied me, five additional pages with classification markings were discovered among the material with it, for a total of six pages. The DOJ officials with me immediately took possession of them," Mr Sauber said.
Mr Biden's legal team acknowledged this week it had found classified documents relating to his time as vice president in the Obama administration at his Delaware home, including some in his garage.
Aides previously found another batch of classified documents at his residence, and at a Washington think tank he was associated with. US Attorney General Merrick Garland named a special counsel on Thursday to probe the matter.
"How many more classified documents will they find at Joe Biden's house?" the Republican House Judiciary Committee said in a Twitter post on Saturday.
Mr Sauber said Biden's lawyers have acted "immediately and voluntarily" to hand all the documents found to the proper authorities.
"We have now publicly released specific details about the documents identified, how they were identified, and where they were found. The appointment of the special counsel in this matter this week means we will now refer specific questions to the special counsel’s office moving forward. As I said Thursday, the White House will cooperate with the newly appointed special counsel," he said.
Mr Biden is spending the weekend in Wilmington with his wife, Jill Biden, who underwent surgery on Wednesday to remove skin lesions from her face and chest.
Mr Biden was asked by a reporter on Thursday about the wisdom of storing important material next to his Corvette. The self-declared "car guy" president said both were in a locked garage.
"It's not like they’re sitting out in the street," he said. "People know I take classified documents and classified material seriously."
Republicans in the US House of Representatives launched an investigation on Friday into the Justice Department's handling of improperly stored classified documents possessed by Biden, and questioned whether his son, Hunter, had access to any.
In a letter to Garland, top Republicans on the House Judiciary Committee demanded all relevant documents and communications between the Justice Department, the FBI, the White House and Biden's attorneys.
On Saturday, James Comer, Republican chairman of the House Oversight Committee, described the matter as alarming and said the National Archives, Justice Department and White House had not been transparent. Mr Comer said his panel would also review the case.
Republicans have sought to compare the investigation to the ongoing probe into how former President Donald Trump handled classified documents after his presidency.
The White House says the two cases are different because Mr Biden's team has co-operated with authorities in their probe and had turned over those documents. Mr Trump had resisted doing so until an FBI search in August at his Florida resort.
Bob Bauer, Biden's personal lawyer, said in a statement that Biden had directed his attorneys to be "forthcoming and fully co-operative with the National Archives and Records Administration and the Justice Department regarding the documents.