President Joe Biden has said people ignore “butcher” Vladimir Putin and his supporter Donald Trump, while focusing on his disturbing gaffes.

“When that butcher Putin invaded Ukraine, Trump called it “genius” and “wonderful,” Mr Biden tweeted on Friday.” But people would rather talk about how I mix up names.”

Mr Biden’s attempt to deflect questions and attention from his mental acuity has been met with criticisms by his followers on X.

This follows his embarrassing gaffes during the NATO summit on Thursday, where he confused Vice-President Kamala Harris for Donald Trump and mistakenly referred to Ukrainian President Volodymyr Zelensky as Russian President Vladimir Putin.

The 81-year-old president, who has faced increasing scrutiny from his party regarding his suitability for a second term, ignited yet another controversy as he struggled with basic details at the international summit.

Asked about Ms Harris’ potential to defeat Mr Trump in the 2024 election, Mr Biden said, “Look, I wouldn’t have picked Vice-President Trump (sic) to be vice-president, did I think she’s not qualified to be president.”

Again, Mr Biden erred when introducing the President of Ukraine during the summit, mistaking him for Vladimir Putin of Russia.

“And now I want to hand it over to the President of Ukraine, who has as much courage as he has determination. Ladies and gentlemen, President Putin. President Putin,” Mr Biden said before realising his mistake and correcting himself.

Mr Biden’s errors further amplified existing doubts about his cognitive decline. In a post on Truth Social, Donald Trump took the opportunity to mock the American president.

“Crooked Joe begins his ‘Big Boy’ press conference with, ‘I wouldn’t have picked Vice President Trump to be vice president, though I think she was not qualified to be president.’ Great job, Joe!” Mr Trump wrote.

Mr Biden’s latest gaffes have gone viral on social media, eliciting concerns over his capacity for office just two weeks after a lacklustre performance in a presidential debate against Mr Trump in June.

During the debate, Mr Biden appeared disoriented and struggled to maintain coherence, leaving many viewers questioning his mental acuity.