WASHINGTON — On Sunday, a significant development unfolded as four additional Democrats in Congress expressed during a phone call their belief that President Joe Biden should step aside to enable a change in the party's nominee for president, according to multiple sources familiar with the discussion.

Advocating for Biden's withdrawal from the race were Adam Smith of Washington, Jerry Nadler of New York, Mark Takano of California, and Joe Morelle of New York. Each holds influential roles on critical committees within the House of Representatives, bringing the tally of Democrats calling for Biden to reassess his candidacy to nearly a dozen.

Smith, the ranking member of the Armed Services Committee, was joined by Nadler from the Judiciary Committee, Takano from the Veterans’ Affairs Committee, and Morelle from the House Administration Committee in their expression of concern.

The hour-long call was convened by House Democratic leader Hakeem Jeffries of New York on Sunday afternoon. Sources familiar with the call revealed extensive deliberation on Biden's future as the party's standard-bearer, with each lawmaker given an opportunity to address their stance, predominantly reflecting concerns over Biden's electability against former President Donald Trump.

While there was no unanimous consensus among these lawmakers, there was a prevailing sentiment that Vice President Kamala Harris might offer a stronger candidacy than Biden, and she was widely regarded as a potential replacement should Biden withdraw from the race.

Representatives Jamie Raskin of Maryland, Don Beyer of Virginia, and Jim Himes of Connecticut, who hold key positions in various committees including Oversight, Joint Economic, and Intelligence respectively, voiced reservations about Biden's candidacy but did not explicitly call for a change in the nominee.

After the call, Beyer reaffirmed his support for Biden, emphasizing his commitment to the Biden-Harris ticket and their collective goal of defeating Donald Trump in the upcoming election. Both Beyer and Himes declined immediate requests for further comment.

In a brief interaction with NBC News, Raskin clarified that he had not advocated for Biden's withdrawal and dismissed assertions that he believed Biden couldn't prevail against Trump in November.

The issue of Biden's age, 81, has been a persistent concern among voters, particularly exacerbated by his widely criticized debate performance on June 27. Lawmakers and donors alike have engaged in discussions over Biden's suitability as the Democratic candidate to challenge Trump, 78, in the forthcoming election.

Representative Susan Wild of Pennsylvania expressed reservations about campaigning with Biden, citing potential implications for down-ballot Democrats. Although she refrained from calling for Biden's withdrawal, her comments underscored broader concerns within the Democratic Caucus regarding Biden's electability.

The Congressional Black Caucus remains largely supportive of Biden, with Representatives Maxine Waters and Barbara Lee staunchly defending him during Sunday's call and in public statements following the debate.

Meanwhile, Representative Frederica Wilson of Florida, also a member of the Congressional Black Caucus, issued a statement in support of Biden and criticized calls for his withdrawal, emphasizing Biden's track record and leadership.

In response to mounting pressure, Biden reaffirmed his determination to remain in the race during an interview with ABC News on Friday and reiterated his commitment during a visit to Pennsylvania on Sunday, where he affirmed that the Democratic Party stands behind him.

Despite these assertions, discussions within Democratic circles on Capitol Hill persist regarding Biden's candidacy, reflecting ongoing deliberations over the party's strategy leading up to the election.