In the span of less than a week, two universities have rescinded commencement speaking invitations to Linda Thomas-Greenfield, the American ambassador to the United Nations, because of student opposition to the United States’ support of Israel during the war in Gaza.

Xavier University, an historically Black institution in New Orleans, withdrew its invitation to Ms. Thomas-Greenfield earlier this week, saying in a statement that “a number of students” had objected to her giving a commencement address. The president of Xavier, Reynold Verret, indicated that he was concerned about the possibility of disruptions during the graduation ceremony this weekend, and came to the conclusion that Xavier could no longer host her — a situation he said was “regrettable.”

Mr. Verret added that he looked forward to having Ms. Thomas-Greenfield, one of only two Black women to hold the U.N. ambassador post, visit the school and speak “in the future.”

The University of Vermont announced last week that Ms. Thomas-Greenfield would not be speaking there, agreeing to a key demand from by student demonstrators who set up an encampment on the campus in Burlington. The school’s president, Suresh Garimella, notified the student body last week that Ms. Thomas-Greenfield would not speak at graduation, and wrote, “I see you and hear you.”

A spokesman for Ms. Thomas-Greenfield said in a statement that the ambassador looked forward “to continuing to engage with young people on campuses” and elsewhere, and noted that she had recently spoken to high school students in Pennsylvania.

Opponents of Israel’s military campaign in Gaza, which has claimed the lives of more than 30,000 people, according to Palestinian health authorities, have focused some of their ire on Ms. Thomas-Greenfield because she has led the U.S. efforts in the Security Council to block several resolutions calling for a cease-fire. She argued against the resolutions on the grounds that Hamas, whose Oct. 7 attack on Israel killed 1,200 people, had not agreed to release the hostages it took that day.

Even so, in March the United States abstained from voting on one cease-fire resolution, a signal of the Biden administration’s growing displeasure with Prime Minister Benjamin Netanyahu’s handling of Israel’s war efforts. That abstention allowed the resolution to pass the Security Council, breaking a five-month impasse.