New York City has received authorization from Columbia University to send the NYPD onto campus, a senior city official told ABC News.

-ABC News' Aaron Katersky

University of Southern California President Carol Folt released a statement Tuesday after being alerted to an alleged swastika drawn on the USC campus.

"I've just been made aware of a swastika drawn on our campus," Folt said in an update on X Tuesday afternoon.

"I condemn any antisemitic symbols or any form of hate speech against anyone. Clearly it was drawn there to incite even more anger at a time that is so painful for our community," Folt continued.

Folt said the university is investigating and that the swastika has been removed.

Columbia University students were told to shelter in place Tuesday evening due to "heightened activity" on the Morningside campus.

"Shelter in place for your safety due to heightened activity on the Morningside campus," the university’s emergency management operations team said in an alert Tuesday.

Officials warned that "Non-compliance may result in disciplinary action" and that students should "avoid the area until further notice."

The City College of New York said it will hold classes remotely starting on Wednesday until further notice due to "current encampment activities" on the Manhattan campus.

Campus buildings will be closed except to essential personnel, the university said.

The announcement comes nearly a week after the university, which is part of the City University of New York (CUNY) system, said a group of demonstrators calling themselves the "CUNY Gaza Solidarity Encampment" set up a tent encampment on the campus' quad.

"The demonstrators appear to be made up of students, faculty and staff from City College and across the CUNY system and a sizable contingent that is not affiliated with any CUNY campus," City College President Vince Boudreau said in a letter to the community earlier this week, noting that school leaders had begun discussions with representatives from the group.

"We are working to minimize risks to people within the encampment and to protect all members of our campus community, while also minimizing the encampment's impact on campus operations," Boudreau said.

NYPD officers entered the campus of the City College of New York late Tuesday night.

"As requested by the university, we are currently on campus to assist the university in dispersing those trespassing," NYPD Deputy Commissioner of Operations, Kaz Daughtry, said in a post on X, sharing video of the police moving in.

In a note to the campus community, university president Vince Boudreau, said protests on campus presented "heightened challenges."

"Most importantly, this is not primarily a CCNY demonstration, and perhaps not primarily a CUNY demonstration. The significant inclusion of un-affiliated external individuals means that we don’t have established connections to them," Boudreau's letter read.

He continued: "Specifically, this demonstration has been more contentious and violent than anything we’ve seen on campus before. Today, we distributed a letter to members of the encampment detailing specific examples of threats to the safety of people within and outside the encampment, so that all of them understand the full scope of the activity. We also want all of them, and those of you reading this note, to understand that in no way does our response to this particular and extraordinary threat overwrite our more fundamental commitments to free speech, academic freedom, or the right to peacefully protest that comply with CCNY and CUNY regulations."

Boudreau said the encamped demonstrators were told to take down their encampment and follow CUNY guidelines for "future activities."

The university president also said classes would be remote on Wednesday due to the situation on campus.

-ABC News' Jolie Lash and Victoria Arancio