Biden was asked to address his gaffe earlier Thursday in which he introduced Ukrainian President Volodymyr Zelenskyy at a meeting about the Ukraine Compact at the NATO summit as Russia's President Putin, and if other world leaders needing to step in and make excuses is "damaging" to America's standing in the world.

"Do you see any damage by me leading this conference?" Biden responded. "Have you seen a more successful conference? I was talking about Putin and at the very end I said, I'm sorry, Zelenskyy."

"I thought it was the most successful conference I've attended in a long time," he later said.

One reporter asked the president, "Have you spent time thinking about what it would mean for your legacy, which you've worked decades to build, if you stay in the race, despite the concerns that voters say they have, and you lose to someone who yourself have argued is unfit to return to the Oval Office?"

Biden replied, "I’m not in this for my legacy. I’m in this to complete the job I started."

Biden began his question and answer session by responding to a question about the growing calls for him to step aside from his campaign.

The president said there was "a long way to go in this campaign."

"So, I am just going to keep moving, keep moving, because look, I've got more work to do, more work to finish," he said.

Asked about what concerns he had about Vice President Kamala Harris' ability to beat Donald Trump, if she were ever to appear on the top of the ticket, Biden confused her with Donald Trump.

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

"The fact is that the consideration is that I think I'm the most well-qualified person to run for president. I beat him once and I will beat him again," he added.