Biden introduced Ukraine's President Volodymyr Zelenskyy as President Putin at a meeting about the Ukraine Compact at the NATO summit Thursday evening.

Biden quickly corrected himself, saying that he was "so focused on beating Putin."

Zelenskyy laughed off the gaffe.

"I'm better," Zelenskyy said.

"You are a hell of a lot better," Biden replied.

The exchange came shortly before Biden was scheduled to hold his first solo news conference since the presidential debate.

-ABC News' Michelle Stoddart

Rep. Marie Gluesenkamp Perez, D-Wash., has become the 14th House Democrat to call for Biden to end his campaign and even questioned if he should remain in office.

Gluesenkamp Perez, who flipped a district in 2022, said in her statement Thursday she had spoken with constituents in the last two weeks and they expressed worry about Biden's age and health.

"Like most people, I represent in Southwest Washington, I doubt the President’s judgment about his health, his fitness to do the job, and whether he is the one making important decisions about our country, rather than [an] unelected advisors," she said.

"The crisis of confidence in the President’s leadership needs to come to an end," the congresswoman added.

-ABC News' Lauren Peller

Senate Democrats met with top Biden campaign officials behind closed doors Thursday for about two hours trying to lay out the path to victory for the president.

One senator said the meeting was 'tense' at times.

A number of senators expressed concerns about the president being shielded by his advisers, two sources with knowledge of the meeting told ABC News.

Some senators stated they were being put in "difficult," "impossible" or "untenable" positions by having to defend the president to constituents back home after the debate, especially for those senators in tough races, according to the sources.

No Biden campaign polling was shared with senators but instead Biden's advisers laid out a strategy, including showcasing the president's record, going after Trump, campaigning on a second-term agenda and building out the coalition of voters, sources said.

One senator who spoke to ABC News said, "I needed to see hard data that showed a path to success in November and we did not get that."

"I continue to have concerns that only Joe Biden can address, not his campaign staff," the senator said.

-ABC News' Rachel Scott and Allison Pecorin

Arizona Democratic Rep. Greg Stanton became the 13th House member to openly call on Biden to leave the race Thursday.

Stanton touted Biden's years of work in his statement but said the president's "most defining legacy, though, is as a fierce defender of American democracy.

"The Democratic Party must have a nominee who can effectively make the case against Trump, and have the confidence of the American people to handle the rigors of the hardest job on the planet for the next four years," Stanton said.

-ABC News' Lauren Peller