Milwaukee, Wisconsin CNN  — 

President Joe Biden faced a new round of defections Friday from Democratic lawmakers publicly calling on him to leave the presidential race, even as his campaign sought to project a message that he isn’t going anywhere.

One day after the Republican National Convention, new public calls for Biden to drop out from a dozen lawmakers – including Democratic Sen. Martin Heinrich of New Mexico and California Rep. Zoe Lofgren, a close ally to former Speaker Nancy Pelosi – grew the list of congressional Democrats to more than 30.

Two House Democrats close to Pelosi, speaking on condition of anonymity given the sensitivity and rawness in the party right now, attributed Friday’s new statements – especially Lofgren’s letter to Biden – to the former speaker and her belief that it is critical for the president and his allies to understand the effort to push him aside is not going away after the Republican convention, despite the campaign’s efforts to quash it.

The president is described by a source with direct knowledge as “seething” at Pelosi. This source said the sentiment only grew Friday when Lofgren, Pelosi’s longtime close lieutenant, released her letter urging Biden to step aside. CNN has reached out to Pelosi’s camp and the Biden campaign for comment on this reporting.

It is a remarkable break between two powerful party elders and longtime allies in enacting key elements of the Biden agenda.

Aides to Vice President Kamala Harris inside and outside the campaign have also expressed unhappiness with Pelosi and her talk of a quick process to find a new candidate should Biden step aside.

To them, “process” means trying to bypass the vice president in the event the president stepped aside. Harris, who has staunchly defended Biden publicly and tried to show unity, spoke with donors on a call Friday afternoon, which she was asked to do by the West Wing, according to campaign officials.

Biden’s campaign hoped to force party unity Friday, releasing a statement from Biden saying he was looking forward to hitting the campaign trail next week after being sidelined with Covid-19.

And Biden campaign chair Jen O’Malley Dillon went on MSNBC’s “Morning Joe” Friday morning to say Biden was “absolutely” in the race.

“Absolutely the president’s in this race. You heard him say that time and time again, and I think we saw on display last night exactly why,” she said. “Joe Biden is more committed than ever to beat Donald Trump.”

Instead, there was a stream of new statements from House Democrats.

The dynamic has played out repeatedly this week, as more and more Democrats have made public their desire for Biden to leave the race – in addition to reports of congressional Democratic leaders pushing Biden about his chances – even as the president repeatedly says he has no intention to drop out.

A Democratic lawmaker told CNN that House Democratic Leader Hakeem Jeffries and his team are not discouraging members from continuing to speak out against Biden’s candidacy.

The source said it was their impression that members were privately being encouraged to make such statements if they felt that way.

For some of those who want Biden to step down, this source said that there is a fear that the public pile-on, which is expected to grow, is overkill and making Biden mad and potentially even more dug in.

This source, who is in touch with the White House, said that while Biden is now more open to the conversation about potentially stepping aside, he “could go either way” and that the people he is listening to aren’t talking publicly.

That concern didn’t stop more calls for Biden to leave the race on Friday.

Lofgren, who served on the House January 6 committee, released a letter she sent to Biden urging him to step aside. “Simply put, your candidacy is on a trajectory to lose the White House and potentially impact crucial House and Senate races down ballot,” she wrote.

Heinrich was the third senator to publicly call for Biden to leave the race, saying he believed it was “in the best interests of our country” for Biden to step aside.

“By passing the torch, he would secure his legacy as one of our nation’s greatest leaders and allow us to unite behind a candidate who can best defeat Donald Trump and safeguard the future of our democracy,” Heinrich said in a statement.

Rep. Greg Landsman, an Ohio Democrat, told Dana Bash on CNN’s “Inside Politics” Friday that it was time for Biden to drop out.

“Passing the torch is the right thing to do,” Landsman said. “That is the way to ensure that Donald Trump doesn’t win the presidency.”

And four other House Democrats – Reps. Jared Huffman and Mark Pocan; a member of the Congressional Hispanic Caucus, Chuy Garcia; and a member of the Congressional Black Caucus, Marc Veasey – released a joint statement Friday, using the same “pass the torch” rhetoric.

“Passing the torch would fundamentally change the trajectory of the campaign,” they said. “It would reinvigorate the race and infuse Democrats with enthusiasm and momentum heading into our convention next month.”

Lawmakers urging Biden to stay in the race have warned about the unchartered waters that the party would enter if Biden were to drop out. Biden’s campaign released a new memo Friday saying that there “is no plan for an alternative nominee.”

DNC officials met by phone Friday for a convention rules committee meeting, where they shared few details on when a virtual roll call to renominate Biden.

During the meeting, party leaders reiterated that voting wouldn’t start before August 1, but didn’t set a specific date. Instead, under the proposed plan, it will be up to party leadership to pick a date at a later time.

The rules committee didn’t take any steps to approve the plan Friday but will meet again next week.

This story has been updated with additional developments.