Watch viral video: In another gaffe, US President Joe Biden calls Kamala Harris 'Vice President Trump'

US President Joe Biden mixed up the name of his vice president, Kamala Harris, and his Republican rival Donald Trump on Thursday as more of the 81-year-old incumbent's Democratic colleagues call on him to end his re-election bid.

Biden faces growing doubts from donors, supporters and fellow Democrats, who fear he no longer has the ability to beat former President Trump in the Nov. 5 election, or to lead the country for another four-year term.

"Look, I wouldn't have picked Vice President Trump to be vice president if she was not qualified to be president. So start there," Biden said as he responded to a question from Reuters about his confidence in Harris.

Things seem to be going from bad to worse for Joe Biden.

After calling Volodymyr Zelenskyy “President Putin” at Nato, in response to a press conference question about his future he calls Kamala Harris “Vice President Trump”. pic.twitter.com/hI0zvwLCC6

— Aubrey Allegretti (@breeallegretti) July 11, 2024

That came a few hours after Biden mistakenly referred to Ukrainian President Volodymyr Zelenskiy as "President Putin."

"Ladies and gentlemen, President Putin," Biden said at the NATO summit in Washington, drawing gasps from those in the room before correcting himself.

NATO members are wrapping up a summit in Washington where they extended support to Ukraine to combat the invasion that Russian President Vladimir Putin launched in February 2022.

Biden's campaign has been on the ropes for two weeks, since his poor debate performance against Trump, 78.

So far, 13 of the 213 Democrats in the House and one of the Senate's 51 Democrats have appealed publicly to the president to withdraw from the race. More could make their concerns public if he fares poorly.

Biden coughed frequently and occasionally garbled his responses at the outset of the news conference, but his responses grew steadier as he fielded questions from reporters. Biden overcame a childhood stutter and has frequently mangled names and misspoke throughout his political career.

'PACE MYSELF'

He said he needed to "pace myself" a little more and complained that his aides sometimes overscheduled him. "I'm catching hell from my wife," he said.

The news conference gave Biden an opportunity to tout his successes on the world stage and criticize Trump. Biden argued Trump would weaken NATO and drive up prices for U.S. consumers by imposing steep tariffs on imported goods.

He took credit for bringing Sweden and Finland into the NATO alliance, and said he brought together 50 nations to support Ukraine. "I think I'm the best qualified person to do the job. To make sure that Ukraine does not fall," he said.

United Auto Workers union officials met on Thursday to discuss their concerns with his candidacy, three sources familiar with the matter said, after endorsing Biden in January. The 400,000-member union has a big presence in industrial states like Michigan that Biden will need to carry to win re-election.

Biden's campaign argued that the debate has not dramatically shifted the race, even as it laid out a narrow path to re-election that acknowledged that it faced an uphill climb in many states he won in 2020.

That did not stop four more Democrats in the House of Representatives from calling on Biden to end his campaign: Brad Schneider of Illinois, Greg Stanton of Arizona, Ed Case of Hawaii, and Hillary Scholten of Michigan.

"For our country's sake, it is time for the President to pass the torch to a new generation of leaders," Stanton said in a statement.

None of the party's leaders in Congress have called for Biden to end his candidacy, though former House Speaker Nancy Pelosi on Wednesday declined to say he should stay in the race.

The campaign has commissioned a survey to test how Vice President Kamala Harris would fare if she were to replace Biden as candidate, according to a source with knowledge of the matter. A Reuters/Ipsos poll released last week found Harris would fare no better than Biden if she were the Democratic nominee, as both were statistically tied with Trump.

Prominent donors like actor George Clooney have called on Biden to drop out, and there were signs that concerns are growing within Biden's campaign operation as well.

The New York Times reported that some longtime advisers were considering ways to convince him to drop his reelection bid, while NBC News reported that some campaign staffers thought he stood no chance of winning the election.

A Reuters/Ipsos poll released last week found Biden and Trump tied at 40% each. Other opinion polls have found Trump leading Biden, and some strategists have warned that Trump stood a chance of winning reliably Democratic states like New Hampshire and Minnesota.

In their strategy memo, the campaign argued that it has always expected a close election and could win by focusing on three battleground states: Pennsylvania, Michigan and Wisconsin.

If he won those states, along with others considered to be reliably Democratic, he would win 270 electoral votes -- the bare minimum needed to secure the presidency. Biden won 306 electoral votes in 2020.

The campaign characterized other battleground states he won in 2020 as "not out of reach."

(Except for the headline, this story has not been edited by DNA staff and is published from Reuters)