US President Donald Trump said on Friday that all documents signed using an autopen under his predecessor Joe Biden have been "terminated".
The announcement, made on his Truth Social account, is legally ambiguous and the latest in a series of attacks levelled at the Biden administration over the former president's use of the autopen.
"Any document signed by sleepy Joe Biden with the autopen, which was approximately 92 per cent of them, is hereby terminated, and of no further force or effect," he wrote. "The autopen is not allowed to be used if approval is not specifically given by the President of the United States."
He accused "radical left lunatics" of taking the presidency away from Mr Biden.
Mr Trump has often sought to drum up outrage over Mr Biden's alleged use of the autopen to sign pardons, executive orders and other documents, saying his predecessor was too senile to govern during his term.
Mr Biden was 81 when he left office this year. Mr Trump is now 79 and will leave office in January 2029.
"I am hereby cancelling all executive orders, and anything else that was not directly signed by crooked Joe Biden, because the people who operated the autopen did so illegally," he wrote.
The President issued a previous declaration on Mr Biden's orders in March, calling them "void, vacant and of no further force of effect".
Various autopen systems have been used by previous presidents, but Mr Trump has said their use under Mr Biden proves the then-president was mentally incapacitated and not in control of the White House.
It is unclear what effect the declaration will have, if enacted, as Mr Biden also signed bills from Congress into law.
The Justice Department in 2005 said the president does not need to sign a bill by hand and can direct an official "to affix the president's signature to such a bill, for example by autopen".
In 2011, The New York Times reported that Barack Obama had become the first president to sign a bill by autopen while in Europe. Paper versions are still sometimes flown to the president for signing.
During his last days in office, Mr Biden issued pardons for people targeted by Mr Trump - including Mr Biden's own son, legislators who probed Mr Trump, a military general who had criticised him and the country's top Covid expert.
