A former national spokeswoman for Sen. Bernie Sanders's now-ended presidential campaign publicly stated her opposition to the Democratic Party's presumptive 2020 nominee.

Briahna Joy Gray took aim at former Vice President Joe Biden on Monday just hours after the Vermont senator endorsed him for president.

"With the utmost respect for Bernie Sanders, who is an incredible human being & a genuine inspiration, I don't endorse Joe Biden. I supported Bernie Sanders because he backed ideas like #MedicareForAll, cancelling ALL student debt, & a wealth tax. Biden supports none of those," she tweeted.

"I look forward to seeing what these task forces come up with: The support of a multitude of progressives hinges on Biden making meaningful concessions to the left -- not just lip service -- not merely symbolic overtures," she added.

I look forward to seeing what these task forces come up with: The support of a multitude of progressives hinges on Biden making meaningful concessions to the left -- not just lip service -- not merely symbolic overtures. https://t.co/coVsKMPAcM — Briahna Joy Gray (@briebriejoy) April 13, 2020

Sanders, who suspended his White House bid last week, endorsed Biden on Monday, saying, "Today, I am asking all Americans … to come together to support your candidacy, which I endorse."

Biden's former boss President Barack Obama, however, has thus far withheld his own endorsement.

"I don't know why President Obama hasn't supported Joe Biden a long time ago. There's something he feels is wrong," President Trump said during a press briefing last week at the White House. "He knows something that you don't know, that I think I know. But you don't know."