Portland police say that at least 30 people have been arrested over their involvement in ongoing protests at Portland State University.

"Additional arrests have been made at PSU’s library after trespassers illegally entered the building again despite efforts to secure it," police said in their statement. "Preliminary count is 30 arrests over the course of the day. Officers will continue to monitor for criminal activity and will make arrests when lawful and appropriate."

Authorities say that officers encountered acts of vandalism, and one suspect deployed a fire extinguisher at an officer during an altercation.

"Seven officers suffered injuries, the most serious was a knee injury that required ambulance transport to the hospital. Other injuries are still being assessed or were minor," Portland police said.

The identities of those arrested will be released once a full list has been completed.

USC has sent an email to the arrested protesters on Thursday evening warning that any student protesters who have been arrested for their "alleged conduct" of criminal trespassing on April 24 will be “referred to the University’s disciplinary process.”

"Please be aware that any further violation of university policies - including but not limited to the university's policies against camping, amplified sound, defying DPS directives, vandalism, harassments, bullying, and theft of property - will result in further discipline up to expulsion as well as an immediate ban from campus," the email obtained by ABC News said.

The Portland Police Bureau announced seven additional arrests were made Thursday evening amid ongoing protests at Portland State University.

The seven arrests came a couple of hours after PPB announced 22 people had been arrested on Thursday, bringing the total to 29 people arrested on Thursday.

PPB said the seven arrests were from "trespassers" breaking "back into the library" by pulling the fence down.

"Arrests have also been made for people refusing to leave the park block at the library," the bureau said in an update on X late Thursday evening.

The Portland Police Bureau said 22 arrests have been made amid the ongoing protests at Portland State University.

"PPB has arrested a total of 22 people during the events on the PSU campus," the bureau said in an update on X Thursday.

Earlier in the day, Oregon Gov. Tina Kotek released a statement condemning vandalism reported at the PSU Library.

“I fully condemn the criminal actions taken Thursday morning that resulted in the burning of 15 Portland Police Bureau cars, endangering first responders and the surrounding community," Kotek said, adding, "This includes the acts of vandalism seen this week at the Portland State University library and against nearby businesses."

New York University and New School, in separate statements, said they requested police move students from their campuses after multiple rounds of negotiations failed.

NYU said the "encampment had become increasingly untenable for the NYU community and the neighborhood we inhabit." Classes will proceed as normal today.

NYU said it is aware of calls for a 4 p.m. protest at the former site of the encampment.

The New School, which switched to remote learning Friday, said students continued to set up in the lobby of the University Center building and block access to the "residence hall, classrooms, library, and cafeteria."

Despite the university "pleading to allow their fellow students to enter their residence hall, the protesters would not budge."

The New School said the protests continued even after they "provided a confirmed date this month for the Investment Committee to consider a vote on disinvestment."

"It is a sad day for all of us who are part of this university community and who believe in free speech, which we have pledged to protect and will continue to protect," The New School said in a statement.