Trump said on his Truth Social platform that the pardons “are hereby declared void, vacant, and of no further force or effect, because of the fact they were done by Autopen.”
US presidents have long used autopens, including to sign bills into law, and there was no evidence Biden had used the signature device on the pardons.
It was unclear what, if any, authority Trump has to void presidential pardons.
Asked by reporters early Monday whether everything Biden signed with an autopen should be voided, Trump said: “I think so. It’s not my decision, that’ll be up to a court.”
Biden issued pardons to former senior Republican lawmaker Liz Cheney and other members of the congressional committee that investigated the Jan 6, 2021 attack on the Capitol by Republicans stirred up by Trump’s false claims to have won the 2020 election.
Other recipients included former Covid pandemic advisor Anthony Fauci, retired general Mark Milley, and close family members including Biden’s son Hunter.
Trump repeatedly promised “retribution” against his political opponents while running in the 2024 election and has sought to crush opposition since taking office.
The president was on Monday visiting the Kennedy Center in Washington, the top arts venue where he installed himself as chairman and ousted the leadership a month ago as part of a war on “woke”.
