Presumptive Republican nominee Donald Trump took a jab at President Joe Biden after Biden mistakenly referred to Trump as his vice president during what his administration described as a “big boy” press conference on Thursday.

Biden made the gaffe immediately after he began taking questions from the media in a rare solo press conference held amid calls for him to step aside as the Democratic Party’s presidential nominee. Trump blasted Biden on Truth Social shortly after the president made the mistake.

“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!” Trump wrote.

Biden’s vice president gaffe wasn’t the only verbal lapse he made on Thursday. Just before the press conference, Biden introduced Ukrainian President Volodymyr Zelensky as “President Putin” at a NATO summit.

JOE BIDEN: “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.” pic.twitter.com/91Rw2B25GR

— Steve Guest (@SteveGuest) July 11, 2024

In another moment that Trump pointed out on his social media platform, Biden said he was “following the advice of [his] commander-in-chief” before correcting himself to say “chiefs of staff of the military.”

The president faced numerous questions from reporters about his increasing mental foibles, but he doubled down on his intentions to continue his re-election campaign and serve as president for a second term if he wins in November. At the end of the press conference, Biden was asked to respond to Trump’s criticism of his gaffe. He smiled and replied, “Listen to him,” before walking out of the room.

A growing number of Democratic lawmakers are urging Biden to end his presidential campaign and allow another candidate to run atop the party’s ticket against Trump. Despite a disastrous debate performance and his failure to calm Democrats’ fears during an interview with ABC News’ George Stephanopoulos, Biden has repeatedly said he is staying in the race.

Trump said earlier this week that he believes Biden would likely remain as the Democrats’ candidate, adding, “He’s got an ego, and he doesn’t want to quit. He doesn’t want to do that.”