US President Donald Trump said his predecessor’s 11th-hour pardons of members of Congress who investigated the January 6 insurrection were “void, vacant and of no further force or effect,” signaling his administration may attempt to upend more than a century of law and practice for presidential pardons.

In a statement on his Truth Social platform just after midnight Monday Washington time, Trump said the pardons were void because Joe Biden signed them with an autopen. His comments follow similar arguments from the conservative Heritage Foundation that Biden used an autopen based on seemingly identical signatures found on several Biden documents. Trump in his Truth Social post did not present any evidence.