Students walk on the University of Michigan campus in Ann Arbor, Mich. The university responded this week to several incidents that have stoked concerns about the effects of anti-Israel attitudes on campus. (Tony Ding/AP)

The University of Michigan this week promised “serious consequences” for instructors whose “personal views” cause them to withhold letters of recommendation, responding to mounting concern that protest against the Israeli state is harming students on the Ann Arbor, Mich., campus.

The announcement follows two separate cases this fall in which a professor and a teaching assistant reneged on their commitments to provide references for undergraduates after learning that the students were applying to study abroad in Israel. The actions have turned the university into a site of contest over the Boycott, Divestment and Sanctions movement, known as BDS.

“Withholding letters of recommendation based on personal views does not meet our university’s expectations for supporting the academic aspirations of our students,” Michigan’s president, Mark S. Schlissel, and the provost, Martin A. Philbert, wrote in a letter to the university community, published online Tuesday. “Conduct that violates this expectation and harms students will not be tolerated and will be addressed with serious consequences. Such actions interfere with our students’ opportunities, violate their academic freedom and betray our university’s educational mission.”

The university leaders said that each case is “being addressed with those involved through our existing policies” and that Michigan doesn’t “share protected personnel information.”

But an Oct. 3 letter obtained by the Michigan Daily spells out punitive measures directed against the professor, John Cheney-Lippold, who last month agreed to support a student’s application for a study-abroad program — until he learned that she was headed to Tel Aviv University.

A dean for Michigan’s College of Literature, Science, and the Arts told Cheney-Lippold, an associate professor of internet and cultural studies, that he would not qualify for a salary increase for the 2018-’19 academic year, according to the campus newspaper, and that his eligibility for sabbatical leave would be frozen for two years. Further conduct of this nature, the dean wrote, would be subject to additional discipline, “up to and including initiation of dismissal proceedings.”

“Faculty are not required to write letters for every student who requests them, and have discretion to decline for legitimate reasons such a lack of time, information about the student, and academic assessment,” the dean, Elizabeth Cole, wrote. That discretion, though, “does not extend to withholding a letter because of your personal views regarding the student’s place of study,” she added, “and then using the student’s request as a political platform to gain an audience for your own opinions, both in the media and in the classroom.”

The American Association of University Professors is monitoring the case but has not yet weighed in, according to Hans-Joerg Tiede, associate secretary in the AAUP’s department of academic freedom, tenure, and governance. He said the organization’s primary concern is with “the apparent absence of academic due process in this case.” AAUP standards for the imposition of major sanctions call for a hearing before a faculty committee, Tiede said, in which the administration must establish that there are grounds for a penalty.

A second episode unfolded just last week, when a teaching assistant in a political theory course, Lucy Peterson, withheld a recommendation letter from a junior, Jake Secker, after learning that he planned to study abroad at Tel Aviv University.

When Secker identified his destination, she said she could no longer provide the reference, according to emails provided to The Washington Post.

“I’m so sorry that I didn’t ask before agreeing to write your recommendation letter, but I regrettably will not be able to write on your behalf,” she explained. “Along with numerous other academics in the US and elsewhere, I have pledged myself to a boycott of Israeli institutions as a way of showing solidarity with Palestine.”

Secker, a native of Great Neck, N.Y., was able to obtain a letter from an associate dean instead, but he and his father weren’t satisfied, telling The Post that Michigan was obligated to follow up on its apology with action. The student’s father, Ed Secker, said the instructor should be disciplined.

Peterson didn’t respond to messages seeking comment, and a university spokesman declined to comment on details of the incident.

Both instructors were labeled anti-Semitic by critics — a charge that Cheney-Lippold vehemently denied in an interview with The Post. He defended his decision to withhold the letter, saying his protest didn’t interfere with his teaching duties and was protected by his academic freedom.

“I can’t prevent a student from going to Israel,” Cheney-Lippold reasoned. “But everybody has the right to withhold something, and I chose to exercise that right based on what the movement needs from me as a solidarity activist.”

Cheney-Lippold is a member of the American Studies Association, which voted in 2013 to endorse BDS. The movement seeks the end of Israeli occupation of “all Arab lands,” the full equality of Arab-Palestinian citizens of Israel and “the rights of Palestinian refugees to return to their homes and properties as stipulated in UN Resolution 194.”

In their Tuesday letter, the president and provost underscored Michigan’s opposition to the boycott of Israeli academic institutions. “Our view is that educators at a public university have an obligation to support students’ academic growth, and we expect anyone with instructional responsibilities to honor this fundamental university value,” they wrote.

A differing view was taken by more than 200 Michigan alumni, who have signed a letter of support for the instructors.

“We write to condemn the disciplinary actions the University plans to take, and to express our opposition to the University of Michigan’s longstanding position on this issue, a position that puts it at odds with international law, the constitutionally protected right to boycott, and its own non-discrimination policy,” the letter states.

The alumni argue that Israeli universities have been “directly complicit in the ongoing occupation through their development of military and surveillance technologies and through their regular violation of the academic freedoms of Palestinians living in Israel, in the West Bank and Gaza Strip, and in diaspora.”

In response to revelations in The Post about a second denial of a recommendation letter, Jonathan A. Greenblatt, the chief executive of the Anti-Defamation League, warned in a statement of a “chilling effect on Jewish and pro-Israel students.”

Adding to the pressure on the university has been outcry over images displayed last week by Emory Douglas, the minister of culture for the Black Panther Party in the 1960s and 70s, at a required lecture for Michigan art students. Slides in the presentation likened Israeli Prime Minister Benjamin Netanyahu to Adolf Hitler and depicted pigs — a highly fraught animal for some Jews — drinking from bottles of money and holding wands with Jewish stars at the end, according to images posted on social media and provided to The Post.

The presentation drew rebuke from Israel’s minister of education, Naftali Bennett, who this week addressed a letter to Michigan’s president saying, “The time has come for you as head of the University to make a strong stand against what has clearly become a trend of vitriolic hatred against the Jewish state on your campus.”

In their letter, the president and the provost apologized to students who were offended but defended the lecture as an exercise of free speech, also saying that Israel hadn’t been singled out for criticism.

But a Michigan senior, Alexa Smith, said the response was insufficient.

“This is not thought-provoking. This is not educational. This is university-endorsed bigotry,” she told The Post.

Cheney-Lippold, in an interview last month, said the controversy had been a useful teaching moment, as he had invited his students to disagree with him and ask him questions, turning the classroom into a safe environment to debate BDS and the Israel-Palestine conflict.

Ruth Eglash contributed to this report.