"I'm fine" Biden: I won't withdraw from the election and I will defeat Trump again

US President Joe Biden has strongly rejected speculation that he might withdraw from the US presidential race, and resumed his campaign on Friday to support his candidacy for a second presidential term.

To chants of "Don't quit" from his supporters at a rally in Detroit, Michigan, Biden said he would defeat "the threat to the nation," referring to his Republican opponent in the election race, Donald Trump.

"There has been a lot of speculation lately. What is Joe Biden going to do? Will he stay in the race? Will he drop out?" the 81-year-old US president said, adding: "Here's my answer: I am a candidate and we will win. I'm not going to change that."

Biden confirmed his position by saying: "My campaign will not collapse, and I will continue to run for the presidential elections, and I will win," adding: "I am the only Democrat who defeated Trump, and I will defeat him again."

The Detroit rally marks Biden's fourth visit this year to a region that is part of the industrial "blue wall," along with Wisconsin and Pennsylvania, states that were key to his 2020 victory over rival Trump.

During a party at a restaurant in Northville, Michigan, Biden tried to reassure voters that he was in good shape, telling his supporters that he would defeat Trump. "We have to finish the job. I can assure you that I am fine."

Biden stressed at a news conference on Thursday, on the sidelines of the NATO summit in Washington, that he will run again and win, ignoring concerns about his age and health after his poor performance in the first presidential debate against Trump two weeks ago.

But a series of gaffes, including referring to his running mate Kamala Harris as “Vice President Trump” and introducing his Ukrainian counterpart Volodymyr Zelensky as “President Putin” on Thursday, have kept Biden’s mental and physical fitness for a second term in doubt.

House Democratic Leader Hakeem Jeffries said he met with Biden late Thursday, as the number of members of Congress calling on the president to withdraw rose to 20.

Jeffries said he and Biden "expressed broad wisdom, honest perspectives and conclusions about the path forward," but gave no further details.

Biden considered himself "the most qualified person to run for president" during a press conference he held yesterday, Thursday, in Washington, rejecting the call to step down before the elections scheduled for November 5.

Biden acknowledged he had to "calm concerns" in the Democratic Party after blaming his gaffes on jet lag and colds, and he also responded in detail to a series of questions on foreign and domestic policy with relatively few errors, although he confused Europe with Asia.

Concerns about Biden are also affecting Democratic donors, especially after Hollywood star and prominent Democratic Party supporter George Clooney called on President Biden on Wednesday to stop his campaign.

The New York Times reported on Friday that a number of other major donors have informed the Biden campaign that about $90 million in pledged donations will remain on hold if Biden continues his candidacy.