The political crisis surrounding President Biden deepened Sunday as the number of House Democrats who are calling on the president to step aside rose to nine after a weekend in which Biden campaigned in the must-win state of Pennsylvania, aiming to shore up his precarious candidacy.

Four senior House Democrats forcefully declared Sunday during an off-the-record call with House Democratic leadership that they believe Biden should step aside: Reps. Jerry Nadler (N.Y.), Adam Smith (Wash.), Mark Takano (Calif.) and Joseph Morelle (D-N.Y.), according to two people on the call. They join five other House Democrats who have publicly called on Biden to drop his reelection bid or have said they believe Donald Trump will beat him in November.

In addition, at least 18 current and former top Democrats as of Saturday had publicly raised concerns about Biden’s fitness for office and his ability to defeat Trump as the president heads into a critical week.

In a moment laden with symbolism, Biden appeared to seek comfort and support from what has historically been his most loyal constituency — Black Americans — at a church service in Philadelphia on Sunday morning.

“The joy cometh in the morning,” said Biden, who has said “the Lord Almighty” is the only one who could talk him out of the race, at Mt. Airy Church of God in Christ. “You’ve never given up in my life. And as your president, I’ve tried to walk my faith.”

The Black community has backed Biden strenuously in recent days as a growing number of elected officials urge the president to show that he can effectively vanquish Trump in November. From the start of the service at Mt. Airy, Pastor Louis Felton was emphatic in his support for Biden, urging worshipers to stand and shout, “We love you, President Biden!”

Felton made a point of noting that the president was sitting next to a 91-year-old bishop, the founder of the church, Ernest C. Morris Sr.

“Don’t let anyone talk about your age,” Felton quipped. “You’re a young whippersnapper.”

At one point during a service that at times seemed designed to boost him during a time of tribulation, Biden seemed to grow introspective, telling the congregation that “we’re all imperfect beings.”

“We don’t know where or what fate will deliver us to or when,” Biden said. “But what we do know is that we can seek a life of light, hope, love and truth no matter what.”

“We have to work together,” the president added. “Because when we do, you can’t stop us.”

Throughout the day, Biden’s campaign sought to show him campaigning before the cameras, backed up by Pennsylvania’s two Democratic senators: John Fetterman, a staunch defender, and Bob Casey, who is up for reelection in November.

The president is entering a critical week that could determine the fate of his campaign as he prepares to host a NATO summit in Washington while Democratic lawmakers return to the Capitol after spending many days hearing from constituents questioning Biden’s stamina and his ability to defeat Trump.

Over the past several days, Biden and his staff have become increasingly adamant that he won’t drop out as the campaign continues to schedule more events to ramp up the president’s visibility. The efforts come as unease grows among Democratic members of Congress and governors, more of whom are calling on him to reconsider his reelection bid after his faltering debate performance.

Meanwhile, elected Democratic officials aired feelings of concern and seemed to be sending messages to the Biden campaign as they took to the Sunday television airwaves.

“You know, invoking God Almighty as the only intervention that is going to dissuade him from going forward, I hope Joe Biden didn’t really mean that,” Rep. Gerry Connolly (D-Va.) said on CNN. “Look, this is a very human process, not a divine process. While we all hope for the blessings of God, politics is a very human business and we have to make some very hard decisions going forward. And so does he.”.

Some prominent senators publicly defended Biden, including Sen. Bernie Sanders (I-Vt.), a former campaign foe turned ally who insisted that Biden could “clearly defeat” Trump.

“What we are talking about now is not a Grammy Award contest for best singer,” Sanders said on CBS’s “Face the Nation.” “Biden is old. He’s not as articulate as he once was. I wish he could jump up the steps on Air Force One. He can’t. What we have got to focus on is policy — whose policies have and will benefit the vast majority of the people in this country.”

During a virtual off-the-record call that ran for almost two hours Sunday afternoon, Democrats leading 24 House committees expressed mixed emotions about whether Biden should stay or go, according to the people on the call who spoke on the condition of anonymity to disclose details of the discussion. Reps. Richard E. Neal (Mass.), Rosa DeLauro (Conn.), Maxine Waters (Calif.) and Robert C. “Bobby” Scott (Va.) fiercely defended the idea of Biden staying in the race, while Minority Leader Hakeem Jeffries (D-N.Y.), Minority Whip Katherine Clark (D-Mass.), Caucus Chair Pete Aguilar (D-Calif.) and other leaders on the call did not voice their opinions on the matter.

Nonetheless, many House Democrats privately insist that it’s time for Biden to step aside. They are considering publicly saying so after the president said in a Friday interview that he had not heard of such concerns from lawmakers he’s spoken to. Biden appears to them defiant and dug in, with little signs that he is considering exiting the race.

The call among House Democrats happened while Biden was trying to rally hundreds of supporters at an outdoor courtyard in Harrisburg, Pa., where he stood as Fetterman emphatically backed him up. Biden worked a rope line for nearly an hour, and declared his desire to find some ice cream.

Earlier Sunday, as Democratic lawmakers prepared to appear on the Sunday talk shows, it was no mistake that Biden joined the congregation at Mt. Airy, a predominantly Black church.

During informal remarks at the community organizing event with union members and local Democrats late in the day in Harrisburg, Biden trailed off numerous times with unfinished thoughts, but told the crowd that “we’re on the cusp of getting so much done.”

“With us working together, we’re going to get a hell of a lot done for the American people,” he said.

The past few days have seemed to reassure Biden, who seems buoyed by crowds cheering him and by the more intimate interactions that he was known for earlier in his career. But there are also signs of problems that could portend a battle ahead.

While he was warmly cheered by a crowd at a middle school gymnasium in Madison, Wis., several voters said in interviews that they’d come to see him because they were worried about his health and wanted him to drop out. And while Sunday’s church crowd was enthusiastic — praying for him, locking arms with him, and chanting “four more years!” after he spoke — not every pew was filled for the rare presidential appearance.

Fetterman, who has been one of Biden’s most enthusiastic backers in the aftermath of the debate, later told a group of campaign volunteers: “There’s only one person in this country who has kicked Trump’s ass in an election, and that is your president.”

“I know what it’s like to have a rough debate, and I’m standing here as your senator,” he said. “There is only one guy that has ever beaten Trump, and he is going to do it twice and put him down for good.”

Biden’s 22-minute interview with George Stephanopoulos of ABC News, which aired Friday night, seems to have done little to soothe the restive mood of the Democratic Party at a moment when Biden is sliding further behind in the polls and a majority of Americans say he is no longer fit to hold office.

In a telling sign of the deepening crisis, Sen. Chris Murphy (D-Conn.), a close ally of Biden, did not directly answer a question about whether Biden should be his party’s nominee during an appearance on CNN’s “State of the Union.” Murphy said the president would have to address voters’ concerns by showing them “whether this is still the old Joe Biden.”

“I support Joe Biden. Period, stop,” Murphy said. “But I know that there are a lot of voters out there that need to be convinced that Thursday night’s debate performance was a bad night. … Ultimately, I’m supporting Joe Biden. I’m going to vote for Joe Biden. But the president needs millions of votes.”

The latest prominent lawmaker to urge Biden to consider advice beyond his inner circle was Rep. Adam Schiff (D-Calif.), who is running for the Senate seat of the late Dianne Feinstein. In an interview with NBC’s “Meet the Press,” Schiff said Biden’s debate performance “rightfully raised questions among the American people about whether the president has the vigor” to defeat Trump, adding his view that Biden “should be mopping the floor” with his opponent.

“Joe Biden is running against a criminal. It should not be even close, and there’s only one reason it is close, and that’s the president’s age,” Schiff said. “He’s obviously talked to his family about this, and that’s important. But he should seek out people with some distance and objectivity.”

Schiff said Biden should be contemplating “whether he made the right decision to run or to pass the torch. That is the most important decision for him to make right now,” he said.

As Biden’s campaign aides insist that his debate performance was an aberration and not evidence of cognitive decline, Biden repeatedly rebuffed questions from Stephanopoulos about whether he would undergo an independent medical evaluation that included neurological and cognitive tests.

Biden repeated his assertion that he gets “a full neurological test every day” by carrying out his presidential duties. Schiff said on NBC that both Trump and Biden should undergo cognitive tests.

Biden planned to return to the White House on Sunday night, ahead of this week’s NATO summit in Washington. On Thursday, he is planning to hold a rare solo news conference, and his advisers also said they were adding a campaign trip on Friday to Michigan along with events a few days later in Texas and Las Vegas.

Both the president and first lady were at the event in Harrisburg.

“Isn’t it really dull when you have a president known for two things: Ray-Ban sunglasses and chocolate chip ice cream?” he said.

Then, he stayed for nearly an hour longer, talking to people one by one along the rope line, in a way that he’s rarely done since his campaign four years ago. He kissed foreheads, grabbed shoulders, and took selfies.

Even as the drumbeat is increasing — and likely to get louder — with more Democrats trying to persuade him to get out of the race, it was the kind of affirmation that has made him more adamant about staying in.

Reston reported from Washington. Mariana Alfaro, Leigh Ann Caldwell, Azi Paybarah and Joby Warrick in Washington contributed to this report.