SYRACUSE, N.Y. — Student protesters continued the seventh day of their sit-in at Syracuse University, but other people left campus after a spate of racist and anti-Semitic incidents reported this month, leaving the campus uncharacteristically quiet amid expanded police presence.

The school remained open, but many faculty members canceled classes and school officials announced that students who chose to leave early for Thanksgiving break would not be penalized.

“It has been really tense,” said Jenn M. Jackson, an assistant professor of political science. “A lot of students have said they don’t feel safe even walking on campus.”

Over the past two weeks, Syracuse “has endured the ugliest of hatred, based on race, national origin and religion,” Chancellor Kent D. Syverud told the University Senate on Wednesday, in remarks both practical and deeply personal.

He said campus police believe one to five people may be involved in the bias episodes.

Syverud said a police investigation had found one of the most recent incidents — in which students reported receiving copies of a racist manifesto shared to their phones from someone nearby, sparking fear and chaos — may have been a hoax, with officers unable to identify anyone who received the document.

Syracuse Police Department spokesman Matt Malinowski said Wednesday night he could not confirm the chancellor’s assertion about whether the document had been shared with individual phones. Asked whether the document had been posted to a website, he said his understanding was a link to it had been found in the ongoing investigation.

Syverud also spoke of threats years ago in the South against his own mixed-race family when he fought to make affirmative action permissible in college admissions. “My kids were threatened, my wife was subjected to many racial epithets, our car tires were slashed, and my kid’s dog was shot,” he said.

“But this is Syracuse. This is 2019. I do not accept this hatred here and now,” he said.

Former vice president Joe Biden, a Democratic presidential candidate, expressed concern on social media. “I am deeply disturbed by the news coming out of my law school alma mater, Syracuse University,” Biden wrote on Twitter on Wednesday. “We are truly in a battle for the soul of this nation, and it requires all of us to stand up together as a country against racism and bigotry.”

Since Nov. 7, a dozen incidents have been reported by the Daily Orange campus newspaper, including racial and anti-Semitic slurs scrawled in the bathrooms of dormitory and classroom buildings, a swastika stamped into the snow across from an apartment building and racial epithets yelled at students.

Late Monday and early Tuesday morning, a racist manifesto was reportedly posted on an online forum, according to Malinowski, and on Tuesday, a professor who is Jewish reported receiving an anti-Semitic email referencing the Holocaust.

On Wednesday, campus officials sought to reassure students and parents there had been no credible or direct threats to the campus, “nor has any student been the victim of a physical altercation. That is why our campus remains fully open and classes continue to be in session.”

The university’s Department of Public Safety doubled patrols, and Syracuse police officers and New York state troopers patrolled on and off campus, school officials said. The university added shuttles and safety escorts for students who were walking. And students signed up to drive others.

On Wednesday, students studied while a guitarist played a Red Hot Chili Peppers song. Maggie Lenkiewicz, a senior born in South Korea, joined the protest for the first time, choosing not to go to class after the incidents changed her perceptions about safety.

“I’ve never really felt any racial bias or anyone targeting me, but this is the first time actually in my life I’m very aware of what I look like and how I might be in danger by just walking alone,” Lenkiewicz said.

Clark Gray, a freshman from the District who lives in a dormitory where racist graffiti targeting Asians and African Americans was scrawled and where a Chinese student reported a racial slur, said residents responded by decorating a wall with sticky notes filled with messages about staying safe, dubbing it the “love wall.”

Despite the positive response in his hall, Gray said students remain anxious.

“Some people are wondering, ‘Who’s next?’ ” Gray said.

Svrluga reported from Washington.