WASHINGTON 

US President Joe Biden mistakenly referred to Ukrainian President Volodymyr Zelenskyy as "President Putin" during a press conference Thursday.

"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," Biden said before quickly correcting himself.

"I'm so focused on beating Putin, we’ve gotta worry about it," he added.

The latest gaffe came amid ongoing discussions about Biden's mental health and his ability to serve another term, with calls for his withdrawal from the presidential race following his poor performance during the first presidential debate against Donald Trump in late June.

Shortly after, Biden held a press conference on the occasion of the final day of the NATO leaders’ summit, which began on Tuesday.

In his remarks, he confused his vice president, Kamala Harris, with former President Trump, referring to him as the vice president when responding to a question.

"Look, I wouldn't have picked Vice President Trump to be vice president if she was not qualified to be president. So start there," he said.

Asked if he is reconsidering lifting the restrictions placed on Ukraine on the use of American weapons on targets in Russian territory, he said he was following the advice “of my commander in chief, my chiefs of staff of the military as well as our secretary of defense and our intelligence people” to determine what is a “logical thing to do” on a day-to-day basis.