By means of Sofia Ferreira Santos, BBC news
ReutersUS President Joe Biden has assured Democratic donors he can still win November's presidential election against Donald Trump after poor debate performance fueled concerns about his candidacy.
The president, 81, attended a series of fundraising events in New York and New Jersey on Saturday and defended his performance in CNN's presidential debate.
Speaking at an event on Thursday, Biden admitted: “I didn't have a great night, but neither did Trump.”
“I promise you we are going to win this election,” he said.
Biden's debate performance was marked by hard-to-follow and shaky answers, raising new fears among some Democrats about whether he is the right candidate to run in this high-stakes election.
Speaking to the BBC's Katty Kay, former Democratic House Speaker Nancy Pelosi said Biden's debate performance was “not great” — while his former communications director, Kate Bedingfield, called it “really disappointing.”
The president said he understood the concerns but vowed to fight harder.
New Jersey's Democratic Governor Phil Murphy attended the fundraiser with Mr Biden and the First Lady – and told Mr Biden that “we are all behind you 1,000%”.
The Biden campaign accepted that the debate had not gone as they had hoped, but said he would not step aside for a new candidate.
Campaign chairwoman Jennifer O'Malley Dillon said Saturday that internal polling after the debate showed “voters' opinions had not changed.”
“It won't be the first time that exaggerated media stories have caused temporary dips in the polls,” she said.
Former President Barack Obama, a close friend of Biden, said on social media that “bad debate nights happen.”
“This election is still a choice between someone who has spent his life fighting for ordinary people and someone who only cares about himself,” Obama wrote.
Hours after the debate, Trump told supporters that he considered the debate a “great victory” for his campaign.
“The problem with Joe Biden is not his age,” Trump, 78, said. “It’s his competence. He’s flat-out incompetent.”
It wasn't just politicians who criticized Biden's performance.
In a striking editorial in the New York Times, his determination to run for re-election was described as a “reckless gamble” and he was advised to do some more self-reflection this weekend.
It said Democrats “must recognize that Biden cannot continue his race and create a process to select someone more capable to take his place.”
Voters in the United States have too expressed concern about voting for either candidate after Thursday's debate.
Lori Gregory, a long-time Democrat, told the BBC she “couldn't handle” the debate and asked: “Is this the best our country can do?”
Rep. Crystal Myers-Barber called it “painful to watch,” but added that she thought “Trump came across as very level-headed and presidential and Biden came across as very weak.”
Democrat Shana Ziolko said she was “frustrated” watching the debate and thought there was no clear winner.
A post-debate poll by liberal pollster Data for Progress found that 62% of likely voters who watched or read about the debate thought Trump won. Only 30% of respondents said Biden won the debate.
Until further polling takes place, fundraising could provide another indication of continued enthusiasm for Biden's candidacy.
Chairwoman Jennifer O'Malley Dillon said in a memo that the campaign had raised more than $27 million (£21.3 million) between Thursday's debate and Friday night.
“After Thursday night's debate, the Beltway class is counting on Joe Biden. However, the data in the theaters of war tells a different story,” she said.
“This election was incredibly close before Thursday, and by every metric we've seen since, it remains just as close,” she added.
