Washington — Six more House Democrats and one Democratic senator have joined the growing ranks of their colleagues urging President Biden to drop his reelection bid, as the pressure campaign against the president shows no sign of subsiding weeks after his disastrous performance in last month's presidential debate.

Four House members — Reps. Jared Huffman of California, Marc Veasey of Texas, Chuy Garcia of Illinois and Mark Pocan of Wisconsin — issued a joint statement Friday calling on Mr. Biden to "pass the torch to a new generation of Democratic leaders." Sen. Martin Heinrich of New Mexico soon became the third Senate Democrat to urge Mr. Biden withdraw from the campaign. They were soon joined by Reps. Greg Landsman of Ohio and Zoe Lofgren of California.

Two of the representatives, Veasey and Garcia, are part of key caucuses on Capitol Hill whose support Mr. Biden has courted and held onto as he tries to quell concerns about his fitness for a second term. Veasey is a member of Congressional Black Caucus and Garcia is in the Congressional Hispanic Caucus.

Mr. Biden met with both groups earlier this month and participated in an economic summit co-hosted by Congressional Black Caucus Chairman, Rep. Steven Horsford, in Nevada on Tuesday. The Congressional Hispanic Caucus' political arm, BOLD PAC, endorsed the president Friday morning.

But Veasey, Garcia, Huffman and Pocan warned in their message, which was directed to the president, that public concerns about his age and fitness are putting at risk what they said should be a winning campaign against former President Donald Trump.

"These perceptions may not be fair, but they have hardened in the aftermath of last month's debate and are now unlikely to change," the lawmakers said. "We believe the most responsible and patriotic thing you can do in this moment is to step aside as our nominee while continuing to lead our party from the White House."

The four House Democrats said the party has a deep bench of young leaders, led by Vice President Kamala Harris, who are prepared to succeed Mr. Biden.

"Passing the torch would fundamentally change the trajectory of the campaign. It would reinvigorate the race and infuse Democrats with enthusiasm and momentum heading into our convention next month," they said. "Mr. President, you have always put our country and our values first. We call on you to do it once again, so that we can come together and save the country we love."

The new insistence from the four House Democrats brings the total number of lawmakers publicly calling for Mr. Biden to step aside from the 2024 race to more than two dozen.

In his statement, Heinrich said Democrats need a candidate who can defeat Trump in November. While the New Mexico Democrat acknowledged it is solely up to Mr. Biden ato decide whether to end his campaign, he believes it's in the country's best interest for him to do so.

"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.

He joins Sens. Peter Welch of Vermont and Jon Tester of Montana, who is in a tough campaign to hold onto his Senate seat, in encouraging Mr. Biden to exit the presidential race.

Mr. Biden has so far bucked the pressure to call off his campaign, maintaining that voters selected him as the presumptive Democratic presidential nominee. While he has spent the weeks since the June 27 debate campaigning and participating in media interviews, the president was sidelined from the trail Wednesday when he tested positive for COVID-19 and returned to his home in Delaware to quarantine.