President Biden took to the podium Thursday for his first solo press conference since November as debate over whether Biden should remain the Democratic nominee reaches a fever pitch. Biden remained defiant, saying he is determined to “finish the job” and reasserting he is best positioned to beat Donald Trump. Biden addressed concerns around his mental fitness.

President Joe Biden: “I’ve taken three significant and intense neurological exams by a neuro — by a neuro — a neurologist. In each case, as recently as February — and they say I’m in good shape, OK?”

But Biden’s performance was far from smooth, as he accidentally called Vice President Kamala Harris “Vice President Trump.”

President Joe Biden: “Look, I wouldn’t have picked Vice President Trump to be vice president, did I think she’s not qualified to be president. So, let’s start there, number one. The fact is that the consideration is that I think I’m the most qualified person to run for president. I beat him once, and I will beat him again.”

Just hours earlier, Biden mistakenly referred to Ukrainian President Volodymyr Zelensky as “President Putin” as the three-day NATO summit came to a close.

President Joe Biden: “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? He’s going to beat President Putin. President Zelensky. I’m so focused on beating President Putin.”

Three more House Democrats called on President Biden to step aside following the news conference.