"We hope they come out tonight, frankly," Trump said on Monday.
"We're expecting it."
He said six defendants would have their sentences shortened.
Inmates serving January 6-related sentences could be released as soon as Monday. (AP PHOTO)
The moves fulfil a campaign promise by the Republican to help supporters who were charged and in many cases imprisoned for crimes committed during the riot, a failed attempt to stop the congressional certification of Democrat Joe Biden's 2020 election victory.
A lawyer for the former leader of the far-right Proud Boys group, Enrique Tarrio, said he expected his client to be released from federal prison.
Some federal inmates serving January 6-related sentences could be released as soon as Monday, a Bureau of Prisons spokesperson confirmed, adding that the bureau was still waiting on official action by Trump.
Thousands descended on the Capitol in 2021 following an incendiary speech by Trump, tearing down barricades, fighting police and sending lawmakers and Trump's vice president Mike Pence running for their lives as they met to formalise the election result.
Proud Boys leader Henry "Enrique" Tarrio's lawyer expects he will be released from jail. (AP PHOTO)
Trump has argued that many of the nearly 1600 people charged in the riot have been treated unfairly by the legal system and in remarks to supporters at the Capitol after being sworn in on Monday once again called them "hostages".
The lawyer for Tarrio, Nayib Hassan, said he was not sure if Tarrio would receive a full pardon or a commutation cutting short his sentence. His mother also posted on X that Tarrio would be released.
Tarrio is serving a 22-year sentence, the longest of anyone criminally charged in the riot, for seditious conspiracy. He was found guilty of plotting to violently oppose the transfer of power after the 2020 election.
A lawyer for Tarrio's co-defendant, Joe Biggs, said he was also told by an intermediary that Biggs is being processed for release. Biggs, who held a senior post in the Proud Boys, was also convicted of seditious conspiracy and sentenced to 17 years in prison.
Speaking to supporters at Washington's Capital One Arena, Trump did not specify how many people he planned to pardon. But the preparations for Tarrio and Biggs suggest that those accused of the most serious crimes over the Capitol attack could be among those receiving clemency.
"We're going to release our great hostages that didn't do - for the most part - they didn't do stuff wrong," Trump said.
He has frequently referred to Capitol riot defendants as "hostages" even though they have been subject to the normal criminal process and many have admitted to or been found guilty of criminal offences.
A source familiar with his plans said earlier on Monday that Trump intends to cut short sentences for some people who attacked police and issue full pardons to people who did not commit violence.
Prosecutors accused Tarrio, Biggs and the rest of the Proud Boys leadership of mobilising for violence after Trump lost the 2020 election and playing a leading role in instigating the breach of the Capitol.
