ABOVE: NYPD officers taking custody of pro-Hamas trespassers at Columbia U on Tuesday. Photo: Charly Triballeau/AFP via Getty Images

By Joe Marino, Craig McCarthy and Emily Crane | The New York Post

Nearly half of the protesters arrested at the Columbia University and City College campuses during violent anti-Israel demonstrations weren’t students, city officials said Thursday — a day after Mayor Eric Adams warned that “outside agitators” were radicalizing youngsters.

Of the 282 protesters cuffed and hauled away during a massive NYPD operation late Tuesday, 134 of them had zero affiliation with either school, Adams and Police Commissioner Edward Caban said in a statement.

Of the 112 protesters arrested at the Ivy League university, 80 were students and 32 were not affiliated with the school.

At the publicly-funded City College, only 68 of the 170 booked were students, while the remaining 102 were outsiders.

“As the anti-Israel protests began to escalate, it became abundantly clear that individuals unaffiliated with these schools had entered these different campuses and, in some cases, were even training students in unlawful protest tactics, many which we witnessed escalating into violent conduct,” Adams said in a statement

“We will not be a city of lawlessness, and we will not allow our youth to be influenced by those who have no goal other than spreading hate and wreaking havoc on our city.”

Hizzoner has repeatedly blamed this week’s on-campus chaos on professionals with a history of fueling non-peaceful protests, and earlier Thursday touted initial figures he said showed that more than 40% of the arrests were of “outsiders.”

“What was given to me by my team, a preliminary review of the numbers, just the beginning process of analyzing, but it appears, though, that over 40% of those who participated in Columbia and CUNY were not from the school and they were outsiders,” Adams told NPR during a media blitz.

The breakdown emerged after Adams repeatedly stated that agitators had descended on Columbia in the lead-up to Tuesday’s operation that saw cops storm the Morningside Heights campus to oust a destructive mob that had illegally taken over the Hamilton Hall academic building.

“There were individuals on the campus who should not have been there,” the mayor insisted Wednesday. “They were people who are professionals and we saw evidence of training.”

The non-students arrested late Tuesday included a 40-year-old man previously busted at demonstrations in San Francisco and the Big Apple who was identified as a “long-time figure in the anarchist world” and anti-governmental “extremist circles,” police sources said.

In addition to facing burglary in the third-degree charges from his April 30 arrest at Columbia, James Carlson was also charged with burning a Jewish protester’s Israeli flag outside Columbia University on April 21 — in what is being investigated as a possible hate crime, Manhattan prosecutors said Thursday.

In 2005, Carlson was charged with suspicion of attempted lynching and aggravated assault on a police officer after allegedly trying to set a cop’s car on fire during a protest in San Francisco, which left the officer with a serious head injury, NYPD sources said.

He was also allegedly involved in protests in January that blocked off entrances to the Holland Tunnel and the Brooklyn, Manhattan and Williamsburg Bridges, sources said.

Carlson was released on his own recognizance at his Manhattan Criminal Court arraignment Thursday and is due back before a judge on June 20.

Rudy Ralph Martinez, 32, who was nabbed at CUNY’s Harlem campus on a burglary charge, is also a serial protester on the anti-Israel front, according to law enforcement sources.

He was captured on camera praising Hamas during a New York City protest in December, video circulating on social media shows.

“One of the greatest days of my life,” a smirking Martinez said as he described the deadly Oct. 7 attack on Israel.

“Long live the resistance,” he added, according to the clip.

Martinez, who cops believe may be currently employed at CUNY after recently graduating from there, has an “extensive history” of protest-related arrests to his name that date back to California in 2012, sources said.

In the Big Apple alone, Martinez’s rap sheet includes a slew of arrests for disorderly conduct, resisting arrest, obstruction and refusal to disperse, according to the sources.

Another demonstrator arrested at CUNY Tuesday, Jacob Isaac Gabriel, 27, also has a slew of protest-related arrests to his name.

Gabriel often shows up to Big Apple protests clad in Black Bloc gear — a tactic used by protesters to shield their identity with ski masks or helmets, police sources said.

He was also allegedly among the hundreds of pro-Palestine protesters who stormed the Macy’s Thanksgiving Day parade, the sources said.

His rap sheet includes recent charges of resisting arrest, disorderly conduct, refusal to move, offenses against public administrators, fighting and trespassing, according to sources.

“What we have seen, and what has been made clear by the evidence emerging after this week’s arrests, is that professional, external actors are involved in these protests and demonstrations,” Caban said in the statement. “These once peaceful protests are being exploited by professional outsiders, and our young people are the ones most at risk. “

The charges doled out at Columbia included burglary, obstruction, criminal mischief, resisting arrest, trespassing and disorderly conduct.833

Those at City College also included assault on a police officer, officials said.

During the parade of arraignments in Manhattan Criminal Court on Thursday protesters used the clothes off their backs to hide their faces from reporters.

Supporters were also spotted outside the court house using their shirts and jackets to cover protesters’ faces as they were released.

During the proceedings, court officers kicked out at least five supporters who disobeyed orders to remain quiet and off their cell phones. ##