Former US vice president reveals he had uncovered documents marked as classified at his home — a latest twist in mushrooming scandal over politicians' handling of America's most sensitive secrets.

"Mike Pence is an innocent man. He never did anything knowingly dishonest in his life. Leave him alone!!!" says ex-president Trump. (AFP Archive)

Mike Pence found documents marked classified at his Indiana home this month which were taken by the FBI, a lawyer for the former US vice president has said in letters to the National Archives.

Pence, seen as an outside bet for the presidency in 2024, had his lawyer inform the National Archives last week of a "small number" of records that were "inadvertently boxed" and transported to his home in Indiana as he left office in 2021.

"Counsel identified a small number of documents that could potentially contain sensitive or classified information interspersed throughout the records," Pence's lawyer, Greg Jacob, wrote in the letter.

He informed the Republican-led House oversight committee about the cache on Tuesday, according to chairman James Comer, who said in a statement Pence had agreed to "fully cooperate with congressional oversight and any questions we have about the matter."

The discovery comes in the wake of the revelations about classified material discovered in President Joe Biden's private office and residence, and allegations that Biden's predecessor Donald Trump obstructed justice over an FBI probe of a much larger stash of government secrets found at his home.

"Former vice president Pence's transparency stands in stark contrast to Biden White House staff who continue to withhold information from Congress and the American people," Comer added, without mentioning the Trump case.

Pence had asked his lawyer to conduct the search of his home out of an "abundance of caution," CNN reported, citing unnamed sources, and the attorney began going through four boxes stored at Pence's house last week.

READ MORE: FBI finds more classified documents at Biden's Delaware home

Trump defends Pence

"Mike Pence is an innocent man. He never did anything knowingly dishonest in his life. Leave him alone!!!" Trump posted on his Truth Social platform.

The development came as Republicans ramped up their probe of classified documents in possession of Biden, who was himself vice president under Barack Obama when they were removed from the White House.

Records were unearthed in a private think tank office where the president used to work in Washington in early November, in the president's Wilmington, Delaware garage on December 20 and in his home library on January 12.

Justice Department officials found six more classified documents during a search of the Delaware house last week.

Comer has asked the think tank for all its communications related to security by February 1, along with a list of employees and others with keycard access and a log of Biden's visitors.

Government officials can face action over civil or criminal violations for mishandling classified records, but sitting presidents cannot be indicted thanks to a Justice Department policy.

Justice Department special counsels Robert Hur and Jack Smith are conducting criminal investigations into the Biden and Trump documents, respectively.

READ MORE: More classified documents found at Biden home

Source: TRTWorld and agencies