Megan Neely left her position as director of graduate studies for the biostatistics master's program "effective immediately," the dean of the school told students in a letter on Sunday, according to the university's newspaper, The Chronicle.

The dean, Mary Klotman, said Duke's Office of Institutional Equity would conduct a thorough review of the program.

The email by Neely, who remains an assistant professor of biostatistics and bioinformatics at Duke, said she was approached by two faculty members who wanted details of first-year students "they observed speaking Chinese (in their words, VERY LOUDLY)" on campus.

One professor from Duke University sent out an email asking Chinese students not to speak Chinese in school building. pic.twitter.com/6xGkIeScJo

— Hua Sirui 华思睿 (@siruihua) January 26, 2019

The faculty members asked for photos of the students to be able to identify them "so they could remember them if they ever interviewed for an internship or ask to work with them for a master's project."

"I encourage you to commit to using English 100 percent of the time," Neely wrote to students in the master's program. The faculty members were upset, she added, because the students were "being so impolite as to have a conversation that not everyone on the floor could understand."

Read also: Better job prospects in China bring more overseas students home

Screenshots of her email circulated widely on social media on Saturday, prompting some students to submit a petition urging the school to investigate what they called her "apparently discriminatory actions against international students."

Klotman and Neely did not immediately respond to a request for comment on Sunday. Reuters could not verify the contents of the email.

In her letter, the dean reassured students there is "absolutely no restriction or limitation" on the language they choose to use on campus.