(NewsNation) — Police officers carrying zip ties and riot shields stormed a Columbia University building being occupied by pro-Palestinian protesters, streaming in through a window late Tuesday and arresting dozens of people.

Police arrested 282 people at Columbia University and the City College of New York overall as tensions rose between local authorities and the protesters.

NYPD Deputy Commissioner of Public Information Tarik Sheppard joined “NewsNation Now” to discuss the latest in the city’s response to student protesters, saying there was an overwhelming number of “professional agitators” mixed in with the students helping them to barricade in Hamilton Hall.

“This is not how the students were locking themselves in. This is how the professional agitators will lock themselves in,” Sheppard says. “I don’t know the exact number, but we feel we were dealing with an overwhelming number of professionals and not the students who belong on that campus.”

Just blocks away at The City College of New York, demonstrators were in a standoff with police outside the public college’s main gate.

Video posted on social media by news reporters on the scene late Tuesday showed officers hauling some people to the ground and shoving others as they cleared people from the street and sidewalks. An encampment at the public college, part of the City University of New York system, has been going since Thursday.

The Associated Press contributed to this report.