US President Joe Biden hit back at his critics following a poor performance in his first television debate with challenger Donald Trump during a campaign appearance in Raleigh, North Carolina, on Friday.
"I would not be running again if I didn't believe with all my heart and soul I can do this job. Because, quite frankly, the stakes are too high," Biden called out to a cheering crowd.
The president appeared fitter than he had during the Thursday evening debate, when he stumbled and paused awkwardly.
"Folks, let me tell you why I'm here in North Carolina ... I'm here in North Carolina for one reason, because I intend to win this state in November," Biden said. "We win here, we win the election."
Biden's performance in Thursday evening's 90-minute debate raised doubts within his Democratic Party regarding his suitability. While no major party leader has come out against Biden, many commentators have expressed scepticism.
"I know I'm not a young man. State the obvious. Well, I know 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. I know right from wrong," Biden said.
"But I spent 90 minutes on the stage debating the guy who has the morals of an alley cat," he said.
Jill Biden, wearing a dress with the word "Vote" written on it, also came out in her husband's defence.
"There is no one that I would rather have sitting in the Oval Office right now than my husband. What you saw last night on the debate stage was Joe Biden, a president with integrity and character who told the truth. And Donald Trump told lie after lie after lie," she said.
Pointing to the tragedies in Biden's life, she said his optimism was undaunted. "His strength is unshakable. His hope is undeterred," she said.