An attorney for Gates, who has been cooperating with prosecutors since pleading guilty in February 2018 to conspiracy and lying to the FBI, did not respond to a request for comment on Saturday.

Ultimately, Mueller did not charge anyone associated with Trump's campaign of working with Russia or WikiLeaks to release stolen information, and Mueller's 448-page report did not accuse anyone of having advanced knowledge of WikiLeaks' plans.

The documents also include email correspondence between Bannon and Jared Kushner, Trump's senior advisor and son-in-law, as well as a "proposal to obtain" and analyse emails belonging to former Secretary of State Hillary Clinton, which was sent to Bannon by a conservative activist.

BuzzFeed filed a Freedom of Information Act request seeking all documents related to the investigation by former FBI director Mueller, and a lawsuit to get access to the documents.