Over the last month, university presidents have been battered by a vocal cohort of alumni and faculty members who have accused them of not being strong enough in their denunciations of antisemitism in the wake of the Hamas attack on Israel.

Now at some high-profile universities that have faced heavy criticism — including Harvard, Columbia and the University of Pennsylvania — presidents are trying to take more direct action to address those concerns about antisemitism.

Columbia suspended two pro-Palestinian student groups on Friday.

At Harvard on Thursday, the university’s president, Claudine Gay, condemned the phrase “from the river to the sea,” which has been called divisive and antisemitic.

At the University of Pennsylvania, the president, Elizabeth Magill, spoke forcefully against antisemitic rhetoric.

And all three universities formed task forces to address antisemitism on campus.

“Let me reiterate what I and other Harvard leaders have said previously: Antisemitism has no place at Harvard,” Dr. Gay wrote in an announcement on Thursday. “While confronting any form of hatred is daunting, the challenges we face tackling antisemitism are made all the more so by its pernicious nature and deep historical roots. But we are committed to doing the hard work to address this scourge.”

Their moves, however, may not quell the anger among donors.

And the actions may only fuel the resolve among pro-Palestinian student activists, who say that they are only speaking up for marginalized, oppressed people living in Gaza. The criticism, they say, is nothing but an attempt to stifle speech and divert attention from a 16-year blockade of Gaza by Israel, backed by Egypt, that has devastated the lives of Palestinians. In addition, many pro-Palestinian students point out that they have faced doxxing and harassment — and they are asking on social media for similar efforts against Islamophobia.

Columbia announced on Friday that it would ban Students for Justice in Palestine and Jewish Voice for Peace through the end of the fall term, saying that they had violated university policies. The groups have been at the center of weeks of intense demonstrations that have sharply divided students and shaken Columbia’s Manhattan campus. The most recent action, including a walkout, attracted roughly 300 students on Thursday.

Gerald Rosberg, the university’s executive vice president, said in a statement that Thursday’s event “included threatening rhetoric and intimidation” and that the groups had taken their actions “despite warnings” not to do so.

The university’s decision will bar the group from holding events on campus or receiving university funding through the end of the fall semester.

“During this especially charged time on our campus, we are strongly committed to giving space to student groups to participate in debate, advocacy and protest,” Mr. Rosberg said. But, he added, groups would have to abide by university rules that require them to receive approval for large gatherings and cooperate with the administration.

Sonya Meyerson-Knox, communications director for Jewish Voice for Peace, a pro-Palestinian group, called Columbia’s action a “horrific act of censorship and an attempt at intimidation,” adding that the students from both groups were doing exactly what they should do — “standing up against war and calling for a cease-fire to save lives.”

Although universities have occasionally tussled with S.J.P. chapters over the years, Columbia’s decision was at least the second punitive action against the network this week.

On Monday, Brandeis University, near Boston, banned its local S.J.P. chapter from holding activities on campus.

In a notice to the group obtained by The New York Times, Brandeis faulted the national steering committee for encouraging chapters “in conduct that supports Hamas in its call for the violent elimination of Israel and the Jewish people.” Such behavior, the notice said, was “not protected by the university’s principles.”

S.J.P. members have insisted that the group is not inherently antisemitic, but researchers and Zionist groups have sharply critiqued that assertion.

At Penn, Ms. Magill, the president, has faced a fierce, but thus far unsuccessful, campaign to oust her, led by Marc Rowan, the chief executive of Apollo Global Management and the board chairman at Wharton, the university’s business school. He has accused her of tolerating antisemitism after a Palestinian writers conference took place on campus.

She, too, has issued a series of statements that have tried to quell the donor revolt.

On Thursday, she announced that the university was investigating “vile, antisemitic messages” that had been projected onto several campus buildings.

“For generations, too many have masked antisemitism in hostile rhetoric,” Ms. Magill said in her message. “Projecting hateful messages on our campus is not debate, it is cowardice, and it has no place at Penn.”

At Harvard, Dr. Gay, beyond administrative moves and statements, has reached out directly to her Jewish constituents. She delivered remarks at the first Shabbat dinner after the Hamas attack. The Oct. 13 dinner, sponsored by Chabad, the Jewish organization, was attended by about 1,000 people, mainly students but also some faculty members, alumni and donors.

Dr. Gay said that over the course of a challenging week, she had learned a lot not only about “the aching pain and grief” of worrying about loved ones in Israel, but about “the pain and grief that many of you’ve been experiencing on our campus for years.”

She paused to let that sink in before adding: “And what I want to say is that Harvard has your back.”

She got a standing ovation. But her statements, at least up to now, have not seemed to pacify the critics.

On Thursday, Whitney Tilson, a former hedge fund manager and a Harvard alumnus, said that he was so angry at Harvard for not standing up to antisemitism that he had declined an invitation to meet with a fund-raising officer from the business school.

“The damage that Harvard has done to its brand since Oct. 7 is only rivaled in history by New Coke and what Elon Musk has done to Twitter,” he wrote.

Mr. Tilson said on Friday that he considered Harvard “the least needy charity on earth” and that he had made only “a few tiny donations over the years.”

“But,” he added, “I also have a megaphone: I sent that email to nearly 10,000 friends and readers on some of my many email lists.”

Dana Goldstein contributed reporting. Kitty Bennett contributed research.