Princeton University professor is under fire for allegedly using a racial slur multiple times during an anthropology lecture.

According to the Daily Princetonian, the college newspaper, several students walked out of professor Lawrence Rosen's lecture after he asked the students what would be worse: a white man punching a black man or a white man calling a black man the N-word? Rosen is white.

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Students said Rosen allegedly used the word twice more when discussing the lecture topic on oppressive symbolism.

“He was describing what is acceptable as free speech and what is not,” student Devyn Holliday told the newspaper.

Another student, Destiny Salter, pointed out that “every single time he used the n-word, he used the word in its entirety. He said, 'You need to suspend your disbelief for the sake of this class.'"

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When junior Malachi Byrd aked Rosen if he’s just going to continue using the word, Rosen allegedly responded and said, “Yes, if I think it’s necessary.”

Salter alleges Rosen said, “I don’t think I need to apologize; I did not oppress anyone.”

Byrd walked out, followed by at least three others.

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Some people took to Twitter to address the issue. Many said the students should’ve been prepared considering the subject of the course.

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"The professor saw how uncomfortable the students were with his language,"  freshman Kevin Ramos told the newspaper. "If he doesn’t respect the students’ opinion, then it’s not worth learning from him." Ramos said he plans to drop the class.

Students filed a complaint with Justine Levine, director of studies for Princeton’s Rockefeller College. Levine said in an email that she will work with the students to resolve the issue.

On Thursday, Carolyn Rouse, chair of the anthropology department, wrote a letter to the editor in defense of Rosen.

“Rosen has used the same example year after year. This is the first year he got the response he did from the students. This is diagnostic of the level of overt anti-black racism in the country today. Anti-American and anti-Semitic examples did not upset the students, but an example of racism did. This did not happen when Obama was president, when the example seemed less real and seemed to have less power,” she said. “I feel bad for the students who left the class not trusting the process. Rosen was fighting battles for women, Native Americans, and African-Americans before these students were born. He grew up a Jew in anti-Semitic America, and recognizes how law has afforded him rights he would not otherwise have.”

Both Rosen, who holds MacArthur and Guggenheim Fellowships, and Byrd were either unavailable or did not respond to requests for comment, the Princetonian reported.