The University of Michigan is investigating allegations of sexual misconduct by its provost, the school’s top academic officer, and has placed him on administrative leave, the university’s president announced Wednesday.

University officials received several reports of sexual misconduct against Martin A. Philbert, the provost and executive vice president for academic affairs, late last week. The university opened an internal investigation Friday, Mark S. Schlissel, the president of the University of Michigan, wrote in a letter to campus Wednesday. The university retained a private law firm, which launched a probe. Campus police are investigating, and Philbert was placed on administrative leave Tuesday, Schlissel announced.

Philbert did not respond Wednesday to messages seeking comment.

Allegations against such a high-level official create immediate complications for the campus, which is widely regarded as one of the top public universities in the country: The office that would normally investigate such allegations reports to the provost.

Schlissel announced he had ordered the office to report to a different administrator.

“We take allegations of sexual misconduct very seriously,” Schlissel wrote, “and our policy is clear: Sexual misconduct will not be tolerated in the University of Michigan community.”

He wrote that he and the school’s board of regents are committed to a thorough investigation. It is early in that process, he wrote, “and no findings or conclusions have been reached.”

“We thank the individuals who have come forward with these allegation,” he wrote. “We know that reporting requires courage.”

A university spokeswoman declined to provide information about the number and nature of the allegations, and whether the complaints were raised by colleagues, students or people outside of the school.

Philbert has been at the university for decades. A professor of toxicology in the School of Public Health, he joined the faculty in 1995 and was named provost in 2017.

The news prompted shock and concern on campus and beyond.

“Today is a sad day for the University,” Jordan B. Acker, a member of the school’s board of regents, wrote on Twitter. “I am angry and deeply empathetic to the survivors … Our community healing starts with first understanding the alleged activities and exactly what happened,” he wrote. “For me, our investigation must be transparent, with sensitivity and understanding for the survivors and their needs, and work to make sure that something like this never happens on our campus again.”

Several faculty leaders did not respond to requests for comment Wednesday afternoon.