Amid increasing calls from fellow Democrats to end his campaign for re-election, U.S. President Joe Biden on Saturday gave no hint that he was considering stepping aside after a pair of defiant public appearances a day earlier.

Biden, 81, is facing a slow-boil uprising from congressional Democrats and some influential donors who have grown concerned he lacks the capacity to defeat Republican Donald Trump, 78, in the Nov. 5 election. A much-anticipated interview the president gave to ABC News that aired Friday evening seemed to do little to temper those worries.

In that interview, Biden said only the "Lord Almighty" could persuade him to abandon his campaign, dismissing the possibility that Democratic leaders could band together to try and talk him into standing down. He held a business-as-usual call with the national co-chairs of his campaign on Saturday, the White House said.

Pressure from Congress seems only likely to ramp up in the coming days as lawmakers return to Washington from a holiday recess, with Biden perhaps facing one of the most consequential weeks of his presidency.

Even as his future will be debated on Capitol Hill, Biden will host dozens of world leaders at a high-stakes NATO summit in Washington and is scheduled to hold what is sure to be a closely watched press conference.

On Saturday, U.S. Representative Angie Craig of Minnesota became the first Democratic member of the House of Representatives in a battleground district to call for Biden to relent.

“Given what I saw and heard from the President during last week’s debate in Atlanta, coupled with the lack of a forceful response from the President himself following that debate, I do not believe that the President can effectively campaign and win against Donald Trump,” Craig, a top 2024 target of House Republican efforts, posted on X.

Some Democratic House lawmakers are circulating two separate letters calling for Biden to step aside, House Democratic sources have said. Many of those lawmakers had been waiting to see the ABC News interview before moving forward.

House Democratic Leader Hakeem Jeffries scheduled a virtual meeting on Sunday with senior House Democrats to discuss Biden’s candidacy and the path forward.

U.S. Representative Lloyd Doggett of Texas, who had previously called on Biden to step aside, told CNN after the ABC interview, "Every day (Biden) delays makes it more difficult for a new person to come on board to defeat Donald Trump."

Meanwhile on the Senate side, U.S. Senator Mark Warner was contacting some fellow Democratic senators to invite them to a possible meeting on Monday to discuss Biden's campaign.

Biden spent Saturday at his home in Delaware, with no public events on his schedule, although he attended an evening church service. Sunday will be a busy day for him, with two Pennsylvania campaign events in Philadelphia and Harrisburg.

At a campaign rally in Madison, Wisconsin on Friday, Biden vowed to stay in the race.

"I am running and gonna win again," Biden told supporters.

Some polls show Trump's lead over Biden widening, and Democrats worry concerns about the president could weigh on down-ballot races.

But Biden registered his best showing yet in a Bloomberg News/Morning Consult tracking poll of battleground states, with Trump leading Biden by only 2 percentage points, 47% to 45%, in the critical states needed to win the November election.

One bright spot for Biden came early Saturday, when the Palestinian militant group Hamas accepted a U.S. proposal to begin talks on releasing Israeli hostages, including soldiers and men, a move that could pave the way for a ceasefire to end the nine-month-old war between Israel and Hamas in Gaza.

Vice President Kamala Harris, the top choice to replace Biden if he were to step aside as the Democratic Party's standard-bearer, spoke in New Orleans at the Essence Festival of Culture, an annual culture and music festival sponsored by Essence magazine, whose target audience is Black women.

Harris attacked former President Donald Trump and the US Supreme Court for taking away abortion rights. The appearance was part of an effort by the Biden campaign to shore up support among Black voters.

Harris on Friday posted a supportive note on X after Biden's rally in Madison, saying the president had devoted his life to fighting for Americans. "In this moment, I know all of us are ready to fight for him," she said.

Margaret Washa, 75, a retired physical therapist from Middleton, Wisconsin, saw Biden at the Madison rally and thought he looked more vigorous, but grew dismayed after watching the interview.

"It's starting to be about him and whether he can do it, and rather than about what's best for our nation, and about turning over leadership to the next generation," she said. "It's time to pass the baton. There are so many good, strong, younger, intelligent, more charismatic Democrats out there."