President Biden attacked Donald Trump at a rally in North Carolina after his “shocking” performance in the presidential debate on Thursday night.
“I don’t walk as easy as I used to, I don’t speak as smoothly as I used to, I don’t debate as well as I used to but I know what I do know.
“I know how to tell the truth,” said President Biden.
His performance at the debate on Thursday night was described as an “unmitigated disaster” by some in his own party after he paused and stumbled his way through, prompting calls for him to step down.
“I give you my word as a Biden, I wouldn’t be running again if I did not believe, with all my heart and soul, I can do this job,” he told the rally on Friday.
Mr Biden attacked the former president’s criminal record, calling Donald Trump a “one-man crime wave”.
“My guess is he set a new record for the most lies told in a single debate,” he added, telling the crowd he spent “90 minutes on the stage debating a guy with the morals of an alleycat”.
Barack Obama tweeted his support for President Biden, saying: “Bad debate nights happen. Trust me, I know.”
Frday night’s rally took place in Raleigh, North Carolina – a state considered pivotal to the Democrats in the election.
Donald Trump beat Mr Biden here by less than 1.3 percentage points in 2020, and is currently favoured to win again by a slightly bigger margin.
After the event, some remained unconvinced Joe Biden should run for president.
“I do not think President Joe Biden can be the Democratic Party’s standard-bearer in 2024,” said former White House director of global engagement Brett Bruen to Sky News’ Yalda Hakim.
“Last night’s performance was astonishingly bad. You cannot just be strong on the teleprompter,” he said.
But Anthony Scaramucci, former White House communications director blamed the president’s poor performance on his preparation.
“He wasn’t prepped right for that debate. He’s an older man,” Mr Scaramucci told Yalda Hakim.
“You don’t fill his head with facts and figures he’s never going to remember.”
There have been repeated calls for President Biden to step down.
It’s “time to talk about an open convention and a new Democratic nominee,” one Democratic politician told Sky’s US partner network NBC News.
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Democratic Representative Jim McGovern told reporters: “I’d be lying to you if I told you I thought it was a great debate.”
Asked if it was time for the party to consider another nominee, he responded, “I haven’t come to any conclusion yet.”
However, while Vice President Kamala Harris acknowledged that President Joe Biden had a “slow start” in the debate, she insisted that he finished “strong”.
The Trump campaign released a video on Friday highlighting Biden’s stumbles. “Last night the world saw who he is. He is unfit to serve,” spokeswoman Karoline Leavitt said.
At a Waffle House restaurant in Atlanta after the debate, Biden told reporters he did not have concerns about his performance. “It’s hard to debate a liar,” he said.