Fifty-six people have been arrested at The New School and New York University after the schools authorized police to clear encampments, according to the New York Police Department.

Forty-three people were arrested at The New School and 13 people where arrested at NYU, the NYPD said.

-ABC News' Aaron Katersky

NYU has requested assistance from the NYPD to "disperse the illegal encampment on their property."

"As per their request, we are on site and our officers will be assisting with the unparalleled professionalism embodied by our police officers," NYPD Deputy Commissioner, Operations Kaz Daughtry, said in a statement on social media.

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.

Linda G. Mills, the president of NYU, posted a statement Friday evening explaining why the school called in the NYPD to break up an encampment on the Greene St. Walkway earlier in the day.

Mills said 14 people who refused orders to leave the area were arrested and the incident was non-violent.

The president said that the police were called in for numerous reasons, including noise complaints from nearby residents and businesses, safety concerns over the crowds of supporters and counter-protesters and escalating threats.

"The encampment had become increasingly untenable for the NYU community and the neighborhood we inhabit," she said.

Mills said three senior administrators spoke with the protesters over the weekend to come to an agreement over shutting down the encampment.

The president said things escalated on Wednesday when a group of people from a May Day march came to the walkway and got into altercations.

The May Day incident and other issues, including threats leveled at NYU administrators, led the school to call the NYPD, according to Mills.

"The university’s senior leadership and I were compelled to conclude that we could not tolerate the risk of violence any longer and that we could not responsibly or in good conscience wait until something drastically worse were to happen in order to act. We needed to bring this to a close," she said.