Trump and his Republican allies have long questioned Biden’s mental acuity and have attempted to overturn some of the presidential pardons and federal rules issued at the end of his term in office.
A Republican-led panel in the House of Representatives has sought testimony from some of Biden’s closest aides, including his first chief of staff, on his “mental and physical faculties” while he was leading the country.
In a statement on Wednesday, Trump, 78, said the American public had been “purposefully shielded from discovering who wielded the executive power” while Biden’s signature was used to endorse documents Trump described as leading to “radical policy shifts”.
“This conspiracy marks one of the most dangerous and concerning scandals in American history,” Trump said.
Biden, now 82 and fighting advanced prostate cancer, has hit back at Trump.
“Let me be clear: I made the decisions during my presidency. I made the decisions about the pardons, executive orders, legislation and proclamations,” he said.
“Any suggestion that I didn’t is ridiculous and false,” Biden said in a statement on Wednesday night.
Scrutiny over Biden’s mental and physical capacity has intensified in recent weeks as a new book accused an inner circle within the former administration of covering up his “physical deterioration” during his ill-fated re-election campaign last year.
Original Sin, written by Jake Tapper of CNN and Alex Thompson of Axios, alleges Biden’s condition during the campaign was said to be so poor that aides discussed giving him a wheelchair.
Biden abruptly ended his re-election campaign last July, shortly after weeks of pressure following his disastrous debate performance against Trump.
Some Democrats, including former US House of Representatives Speaker Nancy Pelosi, have publicly blamed Biden for not exiting the race sooner, which would have given his party more time to anoint a popular replacement.
Early last month, Biden gave his first interview since leaving the White House, maintaining he “[did not] think it would have mattered” if he had left the race sooner.
Shortly after, he announced that he had been diagnosed with an “aggressive” form of prostate cancer that had spread to his bones – which has led to more accusations from the Trump White House that those closest to the former president, including his wife Jill, would have known of his condition earlier.
