"Today, I'm proud to endorse Joe Biden as President of the United States," Warren tweeted.
Both former rivals reached our to her supporters: Biden called Warren the "fiercest of fighters" on Twitter, while Sanders praised her work on women's rights, corruption and healthcare.
The former New York City mayor spent hundreds of millions of dollars of his own money in a bid to secure the candidacy.
Among the some 850 signatories to the #JewsforWarren declaration are Joshua Malina, the “Scandal” actor, Representative Andy Levin and more than 40 rabbis.
"Antisemitism has no place in democracy. When our neighbors are being persecuted, or attacked, or treated unfairly, that impacts all of us."
"What I happen to believe is that right now – sadly, tragically, in Israel, through Bibi Netanyahu – you have a reactionary racist who is now running that country," Sanders said.
The senator from Vermont has said that he will not be attending this year's conference.
On the live site it read: “Died: February 19, 2020. Cause of death: Senator Elizabeth Warren.”
Zimmerman claims that the two Democratic candidates have defamed him in an attempt to gather votes from the African-American community.
The organization, Persist, filed paperwork with the Federal Election Commission on Tuesday and launched a new commercial in Nevada backing Warren's White House bid.