The Rev. Al Sharpton talks with Democratic presidential candidate Sen. Bernie Sanders as they sit down for a breakfast meeting at Sylvia’s Restaurant, Wednesday, Feb. 10, 2016, in the Harlem neighborhood of New York. Sanders is trying to increase his support with African American voters. (AP Photo/Richard Drew)

Members of the Congressional Black Caucus launched a multi-pronged attack Thursday on Sen. Bernie Sanders as a false revolutionary who lacks strong ties to the black community.

The influential African American elected officials are seeking to use their clout to boost Hillary Clinton, Sanders’s rival for the Democratic presidential nod, as she aims to recover from a thumping 22-point loss to the Vermont senator and self-identified democratic socialist in Tuesday’s New Hampshire primary. They officially endorsed the former first lady inside the Democratic National Committee headquarters in Washington (though it was deemed an “unofficial” event) and pledged to vigorously campaign for her in upcoming contests.

Democratic presidential candidate Hillary Clinton gets a much-needed boost to her campaign with an endorsement from the Congressional Black Caucus PAC. (Reuters)

Civil rights icon John Lewis, a Democrat from Georgia, said he never encountered Sanders during the 1960s-era movement against segregation, which Sanders has described as a formative time for him as a liberal activist.

“I never saw him. I never met him,” Lewis said at a news conference of the Congressional Black Caucus PAC, which drove the endorsement of Clinton. “I was chair of the Student Nonviolent Coordinating Committee for three years, 1963 to 1966…. I met Hillary Clinton. I met President Clinton.”

[The Daily 202, Clinton and Sanders brawl for African American voters]

Rep. Hakeem Jeffries (D-N.Y.) said Sanders has been on the “wrong side” of the gun-control debate, agreeing with gun manufacturers whom Jeffries described as “merchants of death” to the black community.

“[Sanders] voted against background checks five times,” Jeffries said.

The high-profile backing from African American elected officials could provide a crucial boost to Clinton as she seeks to win upcoming contests, especially in the South, where black voters make up large portions of the Democratic electorate. The South Carolina Democratic primary is Feb. 27.

One key South Carolina Democrat did not attend the CBC PAC’s news conference. Rep. James Clyburn (D-S.C.), the No. 3 House Democrat, has not endorsed a candidate, though he said recently he might pick a side before his state’s primary. If he does, Clyburn is expected to endorse Clinton.

[Clyburn hints he might endorse in South Carolina Democratic primary]

By contrast, only two House lawmakers have publicly supported Sanders. One, Rep. Keith Ellison (D-Minn.), a member of the CBC, accused the group Thursday of excluding him from its endorsement process.

“CBCPAC endorsed without input from CBC membership, including me,” Ellison tweeted after the news conference, which he did not attend.

“The point is that endorsements should be the product of a fair and open process. Didn’t happen,” he tweeted later.

Sanders is trying to bolster his credibility with the black community as the next primaries approach. On the campaign trail, the senator often mentions his participation in the 1963 March on Washington led by Martin Luther King Jr.

And his activism as a student at the University of Chicago is frequently touted by those introducing him to black audiences. Sanders was arrested as part of a protest of segregated university housing.

Some CBC members criticized young voters, who supported Sanders overwhelmingly in New Hampshire and the Iowa caucuses.

Rep. Cedric Richmond (D-La.) said that once younger votes are engaged in the political process, “they’re going to do their homework” on the candidates, suggesting they may fall away from Sanders.

“Most of the time, if it’s too good to be true, it’s too good to be true,” Richmond said, referring to the argument that some of Sanders’s proposals, such as universal health care and free college tuition, are unrealistic.

“When you start saying ‘free college,’ ‘free health care,’ the only thing you’re leaving out is a free car and a free home,” Richmond said. “Who is going to pay for it? How are you going to pay for it? That is our responsibility to make sure that young people know that…. You don’t just go to who says ‘revolution.'”

The endorsement from the CBC’s political arm comes at a time of rising debate within the black community about how best to promote its interests in the 2016 Democratic primary.

While members of the CBC are among the most influential African Americans in politics, the Clinton-Sanders contest is drawing reaction from other black leaders seen as having power to sway votes, especially among younger people.

One of those figures is The Atlantic’s Ta-Nehisi Coates, perhaps the country’s foremost writer about anti-black racism, who said Wednesday he will vote for Sanders. Benjamin T. Jealous, a former NAACP president, also endorsed Sanders last week.

House Minority Leader Nancy Pelosi (D-Calif) said Thursday that the CBC endorsement is “significant” and signals support for Clinton on a wide range of issues. Pelosi stopped short of endorsing Clinton herself, though she has hinted at support for the former secretary of state in the past.

According to Rep. Gregory Meeks (D-N.Y.), who leads the CBC PAC, the decision to endorse Clinton was made by the PAC’s 21-member board. Not a single member voted for Sanders, Meeks said Thursday, while two members abstained.

Members of the CBC said they will campaign hard for Clinton in South Carolina over the next two weeks and vowed to court activists who might otherwise support the anti-establishment Sanders.

“Not one of [us] is a member of the establishment,” said Rep. Sheila Jackson Lee (D-Tex.) at the news conference. “Each member of the CBC PAC has their own activist, revolutionary, civil rights marching story. We’re going to tell those stories to young people.”

“Most of us come from the ‘hood,” Meeks said. “We are not the establishment. We are from the streets. Mess with us and you will see: we are from the streets.”

Clinton released a statement Thursday praising the CBC for its “fight for progress every day.”

“The stakes in this election couldn’t be higher,” Clinton stated. “I’ll take on the gun lobby to address the epidemic of gun violence. I’ll take on the Republicans who are disenfranchising voters and rolling back voting rights. And I pledge a new and comprehensive commitment to equity and opportunity for communities of color.”

Kelsey Snell and John Wagner contributed to this report.

–A previous version of this article misstated the number of members of the CBC PAC’s board. There are 21, not 19.