The former national press secretary for Vermont Sen. Bernie Sanders' now-suspended presidential campaign called the sexual assault accusation against presumptive Democratic presidential nominee Joe Biden "credible" in a tweet over the weekend, as Biden's campaign continues to adamantly deny the claim.

Briahna Joy Gray, who has been on a social media tear against Biden since Sanders suspended his presidential campaign last week, referred to the claim against Biden by a woman named Tara Reade as "[c]redible sexual assault allegations" in a Sunday tweet highlighting a variety of issues the Sanders campaign largely avoided challenging Biden on during the Democratic primary. (She did not name Reade in the tweet, but hers is the only known assault allegation against Biden.)

Among the other "[i]ssues Bernie (generously) never raised against Biden," according to Gray, are a "pattern of unwanted touching ... Burisma" and "[l]ying abt civil rights record."

MICHAEL MOORE FACES BACKLASH AFTER QUESTIONING BIDEN'S APPEAL AMONG YOUNG VOTERS

Gray said all those issues are "relevant to Biden's electability argument — (his only real appeal)."

Gray's comments indicate there may be at least some in the Democratic Party who are skeptical toward the Biden campaign's denials -- especially among diehard Sanders supporters.

Reade, who was an apparent supporter of Sanders' 2020 campaign, alleges that Biden sexually assaulted her when she was a staff assistant of his while Biden was in the Senate in 1993.

Reade came forward last year when multiple women accused Biden of inappropriate touching as the presidential campaign was just getting underway. At the time, she told a different story, claiming Biden put his hands on her shoulders and rubbed his fingers up and down her neck, but her account was only printed in an article in a local newspaper.

BIDEN BEATS SANDERS TO WIN ALASKA DEMOCRATIC PRIMARY

But Reade recently spoke to a Rolling Stone journalist in more detail and leveled more serious allegations, saying that Biden "penetrated me with his fingers and he was kissing me at the same time and he was saying some things to me."

The campaign and others close to Biden denied it.

"Women have a right to tell their story, and reporters have an obligation to rigorously vet those claims. We encourage them to do so, because these accusations are false,” Kate Bedingfield, deputy campaign manager and communications director for the Biden campaign, said in a statement to Fox News.

A former executive assistant to then-Senator Biden also called Reade's story "clearly false."

"I have absolutely no knowledge or memory of Ms. Reade’s accounting of events, which would have left a searing impression on me as a woman professional, and as a manager," Marianne Baker, who worked for Biden from 1982 to 2000, said. "These clearly false allegations are in complete contradiction to both the inner workings of our Senate office and to the man I know and worked so closely with for almost two decades."

NEW YORK TIMES EDITS BIDEN SEXUAL ASSAULT COVERAGE, DELETES REFERENCES TO PAST INAPPROPRIATE 'HUGS, KISSES AND TOUCHING

Biden, during the controversy around the confirmation of Supreme Court Justice Brett Kavanaugh, said that he thinks women who bring forward sexual assault allegations should be presumed to be correct, according to a Washington Post story at the time.

"For a woman to come forward in the glaring lights of focus, nationally, you’ve got to start off with the presumption that at least the essence of what she’s talking about is real, whether or not she forgets facts, whether or not it’s been made worse or better over time," Biden said. "But nobody fails to understand that this is like jumping into a cauldron."

In recent weeks, more publications have published stories on Reade's allegations, including a New York Times story that said it was unable to find other sexual assault allegations against Biden but did find two of Reade's friends who said Reade had previously discussed the alleged sexual assault with them.

DEMOCRATIC SOCIALISTS OF AMERICA WON'T ENDORSE BIDEN'S WHITE HOUSE BID

Gray has been one of a handful of Sanders supporters more reluctant to throw their support behind Biden after Sanders exited the presidential campaign. She, for example, suggested that Biden "[t]ry Medicare for All" in response to one post from the presumptive nominee asking supporters of Sanders and other former Democratic presidential candidates to back him in November.

Additionally, she tweeted after Sanders dropped out that she would no longer have to play down her support of socialism now that she isn't working for a candidate for the Democratic presidential nomination.

"On the plus side, I can drop the 'Democratic' from my tweets about why Socialism is good," Gray tweeted, adding a winky-face emoji to the end of her post.

CLICK HERE TO GET THE FOX NEWS APP

Gray also previously tweeted that she voted for Jill Stein in the 2016 presidential election. She's joined by people including former Sanders surrogate Shaun King in her reluctance to fall in line behind Biden.

There are also those, like Rep. Ilhan Omar, D-Minn., who endorsed Sanders' presidential campaign, that are urging fellow Sanders backers to coalesce around the presumptive Democratic nominee.

"For those of you who plan to sit this election out or vote for Trump, just stop. The livelihoods of millions of marginalized people are at stake," Omar said in a tweet last week. "We must all fight like hell to get Donald Trump out of the White House and end the rise of fascism in this country."

Fox News' Brooke Singman and Gregg Re contributed to this report.