The FBI has found an additional classified document in a search of former US Vice-President Mike Pence's home in Indiana.

It follows disclosures by his attorneys that they found "a small number" of classified files from his vice-presidency at the home last month.

Pence agreed to the consensual search, he added.

"The Department of Justice completed a thorough and unrestricted search of five hours and removed one document with classified markings and six additional pages without such markings that were not discovered in the initial review by the vice-president's counsel," said adviser Devin O'Malley in a statement on Friday.

The search was conducted by FBI agents from Indianapolis and is not currently linked to other investigations into classified files, CBS, the BBC's US partner, reported.

It is the latest development in a growing controversy over classified documents that has already embroiled both former President Donald Trump and incumbent President Joe Biden.

Trump faces a criminal investigation for allegedly mishandling classified documents, while Mr Biden faces a probe by the US Department of Justice.

Trump has repeatedly denied any wrongdoing and claimed that he declassified any documents he took when he left the White House.

Pence was recently issued a legal summons to testify in the investigation into Mr Trump. Sources have said the subpoena is related to the ex-president's bid to overturn his 2020 election defeat.