(NewsNation) — The Congressional Black Caucus on Monday offered its support to President Joe Biden as the Democratic nominee in the 2024 election, as the incumbent faces pressure from some in his own party to end his reelection bid.

It might be one of the most important congressional endorsements Biden has received since last month’s presidential debate, as it comes from an influential block within the House of Representatives.

Rep. Steven Horsford, D-Nev., and chair of the Black Caucus, wrote in a statement that voters in his state are focused on moving forward, and reject the “divisive politic of those who would like to take us back.”

“They know President Biden and Vice President Harris are fighting for them,” Horsford said. “Like me, they don’t want to see Donald Trump back in the White House and are ready to work and VOTE to ensure that doesn’t happen.”

Biden’s letter to lawmakers

Earlier Monday, Biden said in a letter sent to Democratic lawmakers that he’s “firmly committed” to running in the 2024 election.

Writing in the letter that he’s had “extensive conversations” with party leadership, elected officials and voters over the past 10 days, Biden added they have “good faith fears and worries” about what is at stake in this election.

“Believe me, I know better than anyone the responsibility and the burden the nominee of our party carries,” Biden wrote.

However, “the question of how to move forward has been well-aired for over a week now,” Biden wrote. “And it’s time for it to end.”

Biden has fielded questions over whether he should be the Democratic nominee for president following a highly criticized performance at the first presidential debate two weeks ago. As he debated presumptive Republican nominee and former president Donald Trump, Biden stumbled through his words and appeared at times to be confused. Although Trump made multiple false statements during the debate, concerns over Biden’s age and mental fitness took center stage.

To Democrats in Congress, though, Biden wrote: “I wouldn’t be running again if I did not absolutely believe I was the best person to beat Donald Trump in 2024.”

“We have a historic record of success to run on,” Biden wrote.

Biden rejects calls for him to drop out

So far, three Democratic members of Congress have called for Biden to step down as the party’s nominee for president. But while Rep. Seth Moulton of Massachusetts, Rep. Lloyd Doggett of Texas and Raúl Grijalva of Arizona are the only lawmakers to officially urge Biden to exit the race, there has reportedly been angst among other legislators, donors and strategists. In addition, post-debate polls have shown Biden losing ground to Trump.

Biden himself has acknowledged he had a “bad night,” telling Milwaukee radio host Earl Ingram he “screwed up.”

The president, his campaign and the White House have pushed back against claims the president isn’t ready for another four-year term.

In a pretaped interview with  ABC’s George Stephanopoulos that aired Friday evening,  Biden said his debate performance was “a bad episode” but gives “no indication of any serious condition.”

“I was exhausted. I didn’t listen to my instincts in terms of preparing,” Biden said. ABC offered Trump a similar interview opportunity, which he declined.

Asked by ABC whether he’d taken a cognitive test, Biden answered that he had not.

“No one said I had to,” he said.

He refused to clarify whether or not he would take a full neurological test and share his results with the American people, telling Stephanopoulos, “I’ve already done it” and to watch how his campaign progresses instead.

The night before the debate, Biden said, doctors even gave him a COVID-19 test, which was negative. What he had was just “a really bad cold,” Biden said, a point he reiterated during a Monday phone call on MSNBC’s “Morning Joe.”

On the TV phone-in, Biden dismissed those urging him to drop out of the race.

“I don’t care what those big names think,” he said. “I’m not going to explain anymore what I should or shouldn’t do. I am running.”