The Working Families Party (WFP), which previously endorsed Sen. Elizabeth Warren (D-MA), formally backed Sen. Bernie Sanders (I-VT) on Monday.

The influential left-wing group announced on Monday, the day prior to the March 10 primary contests, that it is backing Sanders’ presidential bid and will work to persuade Warren supporters in joining his movement:

The group commended Warren for running a “groundbreaking campaign” and expressed how fortunate the progressive wing of the Democrat Party is to have two “progressive giants” in the field.

“But with the field narrowing, we believe the choice for working families is clear,” the WFP said on social media.

“We believe that electing @BernieSanders & progressives all the way down the ballot is how we will turn the big bold ideas that both he and @ewarren have championed for decades into reality,” the group stated:

“Bernie Sanders will fight for a Green New Deal, universal health care and a living wage for every worker. Organized capital won’t rest and neither will we,” WFP National Director Maurice Mitchell said in a statement, according to Politico.

Mitchell continued:

We said from the very beginning that there were two progressive champions in this race, and that our North Star was to elect one of them as president. Now, the Working Families Party will marshal its grassroots supporters and staff to help Sen. Sanders win the nomination and defeat Donald Trump.

The Sanders campaign and supporters initially signaled concern after the WFP, which supported Sanders in 2015, backed Warren over the Vermont senator. Sanders ultimately had to address accusations of his supporters launching “hateful, violent and racist threats” toward those associated with the WFP after it endorsed his rival.

As Breitbart News reported:

Black leaders — including Black Lives Matter leaders, like co-founder Patrisse Cullors — signed a letter, which condemned the “hateful, violent, and racist threats” from people who identify as Sanders supporters. A draft of the letter, obtained by Splinter News, claimed that Sanders supporters have called black leaders “Uncle Tom,” “Slave,” and “Cunt.” The alleged threats followed Sanders’ loss of the WFP endorsement, according to the letter.

“This campaign condemns racist bullying and harassment of any kind, in any space,” Sanders said following the release of the letter. “We are building a multiracial movement for justice — that’s how we win the White House”: