The hearing had been set for May 10 but has now been moved to July 7, according to the Los Angeles Times.

Keller faces a maximum sentence of 20 years in jail for obstructing an official proceeding but is expected to receive a far lighter punishment.

Paul Allard Hodgkins was jailed for eight months after admitting to the same offence as the former swimmer.

The 41-year-old was indicted on seven charges but pleaded guilty to one felony count in September 2021 after reaching a deal with prosecutors.

He was identified in video footage taken inside the Capitol Building, in part because he was wearing a United States Olympic Team jacket.

Supporters of American President Donald Trump halted the Joint Session of Congress, which was being held to certify the election of Joe Biden, on January 6 in 2021.

Four people died during the riot.

Trump became the first US President in history to be impeached twice after he incited the mob to invade the Capitol, although he was acquitted after the Senate fell 10 votes short of the two-thirds majority required to convict high crimes and misdemeanours.

Keller earned two Olympic gold medals and one silver with the American men's 4x200 metres freestyle relay team, triumphing at Athens 2004 and Beijing 2008 and finishing second at Sydney 2000.

He also claimed bronze medals in the men's 400m freestyle at Sydney 2000 and Athens 2004.

Keller was known to be a Trump supporter and commercial real estate firm Hoff and Leigh issued a statement after the riot stating that Keller, an independent contractor, had resigned in the wake of the incident.

Both the US Olympic and Paralympic Committee and USA Swimming condemned the riot.