EXTRA: Biden introduces Zelensky as ‘Putin’, calls Kamala Harris ‘Trump’ at NATO summit

US President Joe Biden referred to Ukraine President Volodymyr Zelensky as “President Putin” during the North Atlantic Treaty Organisation (NATO) summit in Washington DC.

During a separate event at the summit, Biden verbally slipped again, referring to US Vice-President Kamala Harris as “Vice-President Trump”.

“Look, I wouldn’t have picked Vice-President Trump to be vice-president if she is not qualified to be president,” Biden said.

He did not correct himself afterwards.

The gaffes come as some leaders of the Democratic Party pile pressure on Biden to quit the presidential race.

Some House Democrats have gone public with their reservations about Biden remaining at the top of the ticket, citing a potential ripple effect on down ballot races.

There have been heightened concerns from within the Democratic Party over Biden’s cognitive ability and age since his halting debate performance against Donald Trump, the presumptive Republican nominee, on June 28.

During the debate, Biden stuttered, delivered slurred ripostes to Trump’s jibes, left his mouth hanging open on occasion, and mangled his talking points.

Biden, 81, blamed a cold and jet lag for his feeble debate performance afterwards.

Some fundraisers and donors have also called on Biden to drop out of the race, amid reports that a Parkinson’s specialist has made visits to the White House in the last year.

Presidency officials have repeatedly swatted posers that Biden is dealing with a neurological ailment.

George Clooney, Hollywood actor and prominent Democratic fundraiser, implored Biden to drop out of the presidential race in an opinion piece in the New York Times.

“This is about age. Nothing more. We are not going to win in November with this president,” Clooney wrote.

The actor’s comments arrived after Nancy Pelosi, former house speaker, said time was “running short” on Biden to decide whether to stay in the race or not.

Biden has insisted that he would remain in the race. On Thursday, a defiant Biden told White House correspondents that he is in the best mental and physical shape to last the distance and defeat Trump in November.

“If I slow down and can’t get the job done, that’s a sign I shouldn’t be doing it,” Biden said.

“But there’s no indication of that yet.”