New York's mayor Eric Adams and NYPD officials said Tuesday (April 30) that "professional outside agitators" had been identified in Columbia University's protests in recent days.

Deputy Commissioner for Intelligence & Counterterrorism, Rebecca Weiner, said these were people known to the department for years.

Deputy Commissioner for Operations, Kaz Daughtry, said charges of burglary in the third degree, criminal mischief, trespassing and disorderly conduct are among the charges individuals could be facing if the police were to arrest them either in Hamilton Hall or the encampment.

Columbia University officials on Tuesday threatened academic expulsion of students who seized and occupied a classroom building, intensifying a nearly two-week standoff between administrators and pro-Palestinian activists on the Manhattan campus.

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The occupation began overnight when protesters broke windows and entered Hamilton Hall, where they unfurled a banner reading "Hind's Hall," symbolically renaming the building for a 6-year-old Palestinian child killed in Gaza by the Israeli military.

Outside the eight-story, neo-classical building - the site of various student occupations on the Ivy League campus dating back to the 1960s - protesters blocked the entrance with tables, linked arms to form a barricade and chanted pro-Palestinian slogans.