Tufts University postponed a Monday event featuring Anthony Scaramucci, a former Trump White House spokesman, after he threatened to sue a student and the school newspaper for defamation following the publication of an op-ed column criticizing him.

Scaramucci, a Tufts graduate, has served on an advisory board at Tufts’ Fletcher School of Law and Diplomacy since 2016.

An attorney representing Scaramucci demanded in a letter that graduate student Camilo A. Caballero and The Tufts Daily newspaper retract “false and defamatory allegations of fact’’ about his client and issue an apology.

In an e-mail to Caballero, Scaramucci said the student had “suggested publicly’’ that Scaramucci had engaged in unethical behavior.

“So either back it up or you will hear from my lawyer,’’ Scaramucci wrote on Nov. 16. “You may have a difference of opinion from me politically which I respect but you can’t make spurious claims about my reputation and integrity.’’

In an interview Sunday night, Scaramucci said he is not trying to limit students’ free speech but will defend himself against an “attack’’ that he called factually inaccurate.

Earlier this month, more than 240 students and administrators signed an online petition calling for Scaramucci’s removal from the advisory board. Scaramucci said he supports the free-speech rights of those who signed that petition and had been looking forward to Monday’s session as an opportunity to speak directly with students about their views.

“I’m shocked that a university that I love and have been a part of for 35 years is silencing that debate because of my request for an apology,’’ Scaramucci said.

Caballero, 26, who attends the Fletcher School, said the former Trump administration official is trying to use his wealth and his position at Tufts to squelch criticism and chill free speech.

“He is someone that uses his money to gain power and his wealth to buy himself into things that will get him attention. And he uses this power as a scare tactic . . . to get people to not exercise their First Amendment rights,’’ Caballero said. “He’s trying to stop me from exercising my First Amendment right, and that’s plain wrong.’’

Scaramucci called on Caballero and The Tufts Daily to retract comments referring to Scaramucci as “unethical’’ and a “man who makes his Twitter accessible to friends interested in giving comfort to Holocaust deniers’’ (referring to a story about The Scaramucci Post polling its Twitter followers about how many Jews were killed during the Holocaust) and for stating that Scaramucci “sold his soul in contradiction to his own purported beliefs’’ for a White House position, according to a letter sent by his attorney.

“Mr. Scaramucci is ready to take legal action to correct these false and defamatory statements — and to prevent any further damage to his reputation — but will refrain from litigation if you retract the false statements and issue a public apology,’’ Scaramucci’s attorney, Samuel J. Lieberman, wrote in a letter dated Nov. 21.

T. Barton Carter, a communication and law professor at Boston University, said that should Scaramucci choose to bring a defamation lawsuit against the student and the paper, it would be very difficult for him to prove his case.

“First of all, he would have to prove that they said something factual — not something that’s an opinion — defamatory, and inaccurate,’’ Carter said. “And then he still has to prove that they had knowledge it was false, or at least had serious doubts.’’

He said it’s “easy to threaten lawsuits,’’ but in most cases of public officials complaining about defamation, legal action does not follow.

Carter Banker, the Fletcher School graduate student who organized the petition, said Scaramucci’s threat to sue was inappropriate, due to his position of authority at Tufts.

“It doesn’t reflect very well on him that he would target a graduate student who was simply expressing his views,’’ said Banker, 26. “Especially since Mr. Scaramucci is no stranger to bad press.’’

In a statement to the Globe, Tufts University spokesman Patrick Collins said the Monday session with Fletcher School students would have addressed Scaramucci’s “background, experience and the petition calling for his removal’’ from the Fletcher board, but it was postponed until these “legal matters’’ are resolved.

“We’re disappointed that Mr. Scaramucci has taken this action,’’ Collins said in the statement.

Gil Jacobson, 21, editor in chief of The Tufts Daily, said the paper would run Scaramucci’s letter demanding a retraction and an apology in Monday’s print edition.

In a pair of op-eds published earlier this month by the university’s student newspaper, Caballero wrote that Scaramucci harms the school’s reputation with his public conduct.

Caballero wrote two editorials that said Scaramucci was unfit to serve on the Fletcher board and called on administrators to remove him from the panel.

“A man who is irresponsible, inconsistent, an unethical opportunist and who exuded the highest degree of disreputability should not be on the Fletcher Board,’’ Caballero wrote of Scaramucci in a Nov. 6 Tufts Daily column. Caballero called on Tufts officials to respond to the petition in a second op-ed dated Nov. 13.

Scaramucci was fired in July after serving 10 days as Trump’s communications director after a New Yorker writer recorded him using vulgar language during an interview. Scaramucci’s comments about fellow Trump staffers were inappropriate for a person in that position, White House spokeswoman Sarah Huckabee Sanders said at the time.

Since then, Scaramucci has continued to speak to members of Trump’s inner circle regularly, he said, and he traveled to Israel last week, where he told the Associated Press he expected to return to politics and help Trump win another term.

Caballero is concerned that by threatening a lawsuit, Scaramucci will focus attention on Caballero’s free-speech rights rather than on whether Scaramucci should serve on the Fletcher board. “This is not an issue about me and him . . . this is about our institution and the board,’’ Caballero said.

Caballero was born in Colombia and immigrated with his mother and two brothers to Stockbridge, Ga., when he was about 9 years old. He’s a graduate of the Georgia Institute of Technology, with a degree in international affairs and is a recipient of the Thomas R. Pickering Foreign Affairs Fellowship. He hopes to join the State Department as a foreign service officer after completing studies at the Fletcher School next month.

Caballero is not concerned that publicly criticizing a former Trump official will affect a future State Department job. He said his focus has been to demand that school administrators say whether Scaramucci is “worthy’’ enough to hold a seat on the Fletcher board. “If the answer is yes, they need to explain why,’’ Caballero said.

Globe correspondent Martha Schick contributed. Material from the AP and New York Times was used in this report. John Hilliard can be reached at john.hilliard@globe.com