An instructor at Stanford University has been removed from teaching duties as the school investigates reports that during a discussion on the conflict between Israel and Hamas, the instructor downplayed the Holocaust and singled out students "based on their backgrounds and identities."

"Without prejudging the matter, this report is a cause for serious concern. Academic freedom does not permit the identity-based targeting of students," Stanford said in a statement Wednesday.

"The instructor in this course is not currently teaching while the university works to ascertain the facts of the situation," the statement continued.

The instructor, who is not a faculty member, has not been named.

The university's action comes as fierce fighting this week between Israel and Hamas militants in Gaza has increased tensions beyond the Middle East.

Some Jewish people in the US say they fear being targeted as the country contends with widespread reports of antisemitism. Last year, the Anti-Defamation League, which tracks antisemitic incidents, recorded nearly 3,700 incidents in the US, the highest amount since tracking began in 1979.

The Stanford instructor's alleged comments came during two classes Tuesday, with a total of 18 students, during which the instructor announced the day's lesson would focus on colonialism, the San Francisco Chronicle reported, citing Jewish student leaders who spoke with students in the course called College 101, a required class for first-year students.

Nourya Cohen and Andrei Mandelshtam, co-presidents of the Jewish Student Association at Stanford, said the students told them the instructor asked Jewish students to raise their hands, separated those students from their belongings and said he was simulating what Jews were doing to Palestinians, the Chronicle reported.

The students Cohen and Mandelshtam spoke with asked to remain anonymous, the Chronicle said.

Cohen and Mandelshtam declined CNN's request for comment.

In one of the classes, the students say the instructor "asked how many Jews died in the Holocaust," and when students responded 6 million, the instructor said, "Yes. Only 6 million," the students told Cohen, according to the Chronicle.

Students told Cohen and Mandelshtam that the instructor brought up the colonization of Congo by Belgium's King Leopold II in the 19th century and said more people were killed then than during the Holocaust, and that Israel had colonized Palestinians, the Chronicle reported.

Students from both classes told Cohen and Mandelshtam the instructor asked students where their ancestors were from and labeled them as a "colonizer" or "colonized," according to the Chronicle.

"I feel absolutely dehumanized that someone in charge of students and developing minds could possibly try and justify the massacre of my people," Cohen told the newspaper. "It's like I'm reliving the justification of Nazis 80 years ago on today's college campus."

Some of the students said they were afraid to speak up out of fear their grades would be penalized, according to the director of the Chabad Stanford Jewish Center, who spoke with the Forward, a non-profit Jewish news outlet.

"What are they going to do -- get in a fight with their teacher at Stanford?" Rabbi Dov Greenberg told the Forward.

Greenberg spoke with three students in the class and said they were traumatized by the instructor's comments, according to the Forward.

"He's saying Israel is worse than the Nazis and Hamas is innocent. This is what Jewish students face at Stanford and other places. They're feeling isolated, under attack and threatened," Greenberg told the Forward.

The instructor's reported comments come months after Stanford's campus police department opened a hate crime investigation into an antisemitic drawing discovered on a whiteboard attached to a Jewish student's dorm room door.

And in February, multiple swastikas, the N-word and the letters "KKK" were scratched into a metal panel in a bathroom on campus, the university said.

"We have heard many expressions of concern regarding student safety. We have heard from Jewish students, faculty, and staff concerned about rising antisemitism. We have heard from Palestinian students who have received threatening emails and phone calls," Stanford said in its Wednesday statement. "We want to make clear that Stanford stands unequivocally against hatred on the basis of religion, race, ethnicity, national origin, and other categories."