The Congressional Black Caucus' political action committee on Thursday formally endorsed Hillary Clinton for the Democratic presidential nomination, saying the former secretary of state has spent her career dedicated to causes important to them.

"When we needed someone to rally Democrats, and especially African Americans, Hillary Clinton has been there. When there are issues that were important to our constituents, Hillary Clinton has been there," Rep. Gregory Meeks, D-N.Y., chairman of the CBC PAC, said at a news conference in Washington on Thursday morning, according to The Washington Post.

"She's been our partner long-term. We believe she's made a difference, and she has helped us and helped this country by helping elect Democrats across the board," he added.

The endorsement was issued after the CBC PAC's 19-member board privately voted to back her. Rival candidate Vermont Sen. Bernie Sanders received no votes and two people abstained, according to The New York Times.

The CBC PAC made sure to note that the endorsement was not made on behalf of the caucus' 46 members, but only on behalf of the board, which reportedly did not consult with the other members. At least 36 members of the caucus have backed Clinton, according to the Times.

It's a serious blow for Sanders, who along with Clinton, is scrambling to solidify support among the large percentage of black Democratic voters in South Carolina ahead of the Feb. 27 primary election. The CBC PAC said it will send as many as 12 members to campaign in the state for Clinton over the weekend, and will also donate the maximum allowed amount to her campaign.

For his part, Sanders just picked up a historically large 22-point win in New Hampshire, which along with a Wednesday meeting with Rev. Al Sharpton and the backing of influential black author Ta-Nehisi Coates and singer Harry Belafonte, leaves Clinton supporters worried that he could start winning over her black votes.