WASHINGTON Steve Bannon, a onetime adviser to former President Donald Trump, has been subpoenaed by a federal grand jury in Washington in connection with special counsel Jack Smith's investigation into the Jan. 6, 2021, attacks on the U.S. Capitol, NBC News reported on Wednesday, citing sources.

The subpoena, for documents and testimony, was sent out in late May, NBC News reported, citing two sources familiar with the matter.

U.S. Attorney General Merrick Garland tapped Smith last year as special counsel to oversee probes into the former president's handling of classified documents and into a wide range of actions surrounding his 2020 presidential election loss that culminated in his supporters' attack on the U.S. Capitol on Jan. 6, 2021.

Bannon was found guilty in July 2022 of contempt of Congress for defying a demand to appear before a committee investigating the Capitol attack. He has appealed that verdict and has yet to be sentenced.

Separately, Bannon is set to go on trial on May 27, 2024, on criminal charges over a push to fund the former U.S. president's wall along the U.S. southern border, a New York judge said late in May.

The special counsel's office did not immediately respond to a request for comment. Bannon could not immediately be reached for comment. Both declined a comment to NBC News.

(Reporting by Kanishka Singh in Washington; Editing by Rami Ayyub and Matthew Lewis)