President Joe Biden has vowed to continue his reelection campaign during a high-stakes solo news briefing, dismissing concerns about his health and saying he will keep moving despite a growing list of Democratic officials calling for him to step aside.

President Biden showed flashes of anger, defensiveness, boastfulness and defiance as he declared that he will remain in the presidential race against former President Trump.

Biden defended his viability atop the Democratic ticket amid growing calls from lawmakers for him to step aside, laying out the case for his candidacy, even as he made a high-profile gaffe at a closely watched press conference.

The president was adamant he was the best man to take on former President Trump in November, despite others in the party openly questioning whether that was the case, as he held court with reporters for nearly an hour.

“I wouldn’t have picked Vice President Trump to be vice president did I think she was not qualified to be president,” Biden said, confusing his running mate with his opponent in response to the first question of the night.

Biden’s high-profile gaffe, confusing Vice President Harris with former President Trump shortly after he mistakenly introduced Ukrainian President Volodymyr Zelensky as “President Putin,” threatened to overshadow what was otherwise a relatively strong showing in which the president fielded questions about foreign policy, confronting Russia and China, and the risks for the U.S. if his successor pulls back from the world stage.

While the president and his staff remain publicly adamant he will stay in the race, more allies have urged him to pull out, including Vermont Sen. Peter Welch and more than a dozen House Democrats, including three who made the call after tonight’s news conference.

In addition, Barack Obama and Nancy Pelosi have spoken privately about the future of his 2024 campaign. Both the former president and ex-speaker expressed concerns about how much harder they think it’s become for the president to beat Donald Trump. Neither is quite sure what to do.

Meanwhile, the Republican National Convention, where the GOP will nominate Trump as its presidential candidate, is set to kick off next week in Milwaukee.