"His reckless personal conduct since his diagnosis, the destabilizing effect it's having on our government, is unconscionable," Biden said on Friday, referring to the US president, who was hospitalized for three nights last week after being diagnosed by the coronavirus, which knocked him off the campaign trail.
"He didn't take the necessary precautions to protect himself or others. And the longer Donald Trump is president, the more reckless he gets," Biden added.
Trump is set to resume his in-person campaigning in a rapid return to election trail after being sidelined by Covid-19.
Trump will give a public speech at the White House on Saturday while a Florida rally is on his agenda for the next week to relaunch his stumbling reelection campaign against surging Biden.
Trump has repeatedly asserted that he's been fine since leaving the hospital. On Friday, he announced that he stopped receiving medication.
On Friday, the US Commission on Presidential Debates cancelled the second showdown between Trump and Biden after the president declined to do a virtual debate.
"Each (candidate) now has announced alternate plans for that date," the commission said in a statement. "It is now apparent there will be no debate on October 15."