A billboard truck drove near Harvard's campus Wednesday displaying the names and photos of Harvard students whose organizations signed a statement blaming solely Israel for the deadly attacks by Hamas.

The "doxxing truck" appeared days after the Harvard Palestine Solidarity Groups, a coalition of Harvard student groups, earlier this week released a statement that held "the Israeli regime entirely responsible for all unfolding violence," following the attacks by Hamas that have killed more than 1,200 Israelis and more than 25 American citizens. More than 1,400 in Gaza have also been killed since Israel started strikes on Gaza following the deadly Hamas attack.

Some students and their groups have since distanced themselves or withdrawn their endorsements from the statement amid an intense backlash inside and outside of Harvard. Several said they did not read the statement before they signed it.

A conservative nonprofit said it organized the truck featuring the virtual billboards with students' names and images under a banner that reads: "Harvard's Leading Antisemites." It also published names online. CNN has not independently verified that the named students were associated with the letter.

The group's president said in a post on X, the platform formerly known as Twitter, that the group "is removing the names of students from groups that withdrew but are also adding new names every hour."

The University's Hillel, its Jewish student organization, condemned the billboard truck and attempts to intimidate signatories.

"Harvard Hillel strongly condemns any attempts to threaten and intimidate co-signatories of the Palestine Solidarity Committee's statement, including the bus on campus displaying the names and faces of students affiliated with the groups who have signed it," the organization said in a statement posted on its website.

"We will continue to reject the PSC's statement in the strongest terms — and demand accountability for those who signed it," the statement added. "But under no circumstances should that accountability extend to public intimidation of individuals."

Harvard legal scholar Laurence Tribe also blasted the attempts to expose the students, telling CNN in an email that naming and shaming the students, as well as "labeling them as antisemites while posting their photos to put targets on their backs" is "far more dangerous than useful."

"We shouldn't repeat the McCarthy era's excesses in the interest of moral clarity," Tribe added.

In the wake of the mounting backlash, at least eight of the original 34 co-signing Harvard student groups had withdrawn their signature from the statement as of Wednesday afternoon, according to the Harvard Crimson student newspaper.

The reversal from a handful of student groups also comes after billionaire hedge fund CEO Bill Ackman and several other business leaders demanded Harvard University release the names of student signatories so they would know not to hire them.

In a post on X on Wednesday, famed economist and former Harvard President Larry Summers, who criticized the statement, added that it is "not a time where it is constructive to vilify individuals."

"Please everybody take a deep breath," he wrote. "Many in these groups never saw the statement before it went out. In some case(s) those approving did not understand exactly what they were approving. Probably some were naive and foolish."

Harvard referred CNN's request for comment on the doxxing truck to a letter written to the Harvard community and shared online from Executive Vice President Meredith Weenick, which said the university "takes seriously the safety and wellbeing of every member of our community."

"We do not condone or ignore intimidation," Weenick wrote. "We do not condone or ignore threats or acts of harassment or violence."

She added the Harvard University Police Department has "stepped up its security presence on campus and continues to monitor online activity for the potential of any specific threat to the campus community or individuals on campus."

Weenick also included a link to guidance resources on cyber harassment and other electronic threats in her memo.

--CNN's Matt Egan contributed to this report.