STORY: On campaign stops in the battleground state of Pennsylvania on Sunday, embattled U.S. President Joe Biden worked to ease mounting concerns from fellow Democrats about his candidacy.
The 81-year-old has faced growing calls to end his reelection bid after a shaky debate performance against Republican Donald Trump in late June, which raised questions about his ability to do the job for another four years.
Biden has vowed to stay in the race, and in a fundraising email on Saturday, he dismissed calls for him to drop out as "nonsense".
The Democratic president received a warm welcome at a Black church in Philadelphia, and during a six-minute speech, joked about his age.
"Folks I know with every fiber of my being, I know I look like I'm 40 years old, but I've been around a little bit."
Black voters are a critical part of Biden's base, but recent public opinion polling has shown their support for him waning.
"Well, there are those who want to erase history, Kamala and I want to make it, because Black history is American history."
Biden later traveled to the state capital, Harrisburg, for an event with union members.
Asked there if the Democratic Party was behind him, Biden told reporters "yes."
However, on a leadership call the same day called by House Democratic Leader Hakeem Jeffries, a source familiar with the discussions told Reuters that some House Democrats said that Biden should step aside as presidential candidate.
House Democratic sources have said that two letters are circulating among House Democrats calling for Biden to withdraw.
And on Sunday, Democratic National Committee member Alan Clendenin joined calls for Biden to leave, saying "this election is about the next four years, not the last three and a half."
The DNC has steadfastly supported Biden since his debate stumbles, so any defections could suggest a deepening of the crisis.
DNC Chair Jaime Harrison, meanwhile, said that Biden remains the party's nominee.
Democrats have suggested that Vice President Kamala Harris, seen as the likeliest candidate to replace Biden in the November election were he to bow out, could perform well.
