Former Donald Trump advisor Steve Bannon has been released from prison after spending four months behind bars.

Bannon, 70, was released from a Danbury, Connecticut, correctional facility on Tuesday, Benjamin O'Cone, a Bureau of Prisons spokesman, told the BBC.

Bannon, a conservative podcast host who was key to Donald Trump's 2016 presidential campaign, was convicted of two counts of contempt of Congress in 2022 for refusing to comply with a congressional subpoena related to a January 6 Capitol riot investigation.

“The four months in federal prison not only didn’t break me, it empowered me,” Bannon said on his podcast following his release.

“I am more energised and more focused than I’ve ever been in my entire life.”

Bannon is expected to hold a news conference in New York City later Tuesday.

Before he was sent to jail, he promised to continue to help Trump and his campaign from behind bars.

"I've served my country now for the last 10 or so years focusing on this," he told the BBC before going to prison, referring to politics and Trump's Make America Great Again slogan. "If I have to do it in a prison, I do it in a prison - it makes no difference at all."

Bannon has remained loyal to Trump and hostile towards Democratic figures, despite a falling out between the two during Trump's presidency.

"I’m a political prisoner of Nancy Pelosi, I’m a political prisoner of Merrick Garland; I’m a political prisoner of Joe Biden and the corrupt Biden establishment," he said before going to jail.

The Trump loyalist claimed on his podcast in May that Democrats were "going to do everything to steal this election".

He has repeatedly falsely claimed that the 2020 presidential election was stolen.

Bannon is still facing other legal troubles - having been indicted on charges of money laundering, fraud and conspiracy in a separate New York state case in 2022.

He has been accused of cheating donors to a fundraiser that promised to build a portion of a wall on the US-Mexico border. Bannon has pled not guilty to the charges.