Agents with the Department of Homeland Security searched two university residences with a warrant on Thursday evening.
The US Justice Department is investigating whether Columbia University concealed "illegal aliens" on its campus, one of its top officials said on Friday, as the Trump administration intensified its campaign to deport foreigners who participated in pro-Palestinian demonstrations at the school last year.
Agents with the Department of Homeland Security searched two university residences with a warrant on Thursday evening.
No one was arrested and it was unclear whom the authorities were searching for, but by Friday afternoon, US officials had announced developments related to two people they had pursued in connection with the demonstrations.
A Columbia doctoral student from India whose visa was revoked by the Trump administration fled the US on an airliner.
And a Palestinian woman who had been arrested during the protests at the university last April was arrested by federal immigration authorities in Newark, New Jersey, on charges that she overstayed an expired visa.
Deputy Attorney General Todd Blanche, speaking at the Justice Department, said it was all part of the president's "mission to end antisemitism in this country".
"Just last night, we worked with the Department of Homeland Security to execute search warrants from an investigation into Columbia University for harbouring and concealing illegal aliens on its campus," Blanche said. "That investigation is ongoing, and we are also looking at whether Columbia's handling of earlier incidents violated civil rights laws and included terrorism crimes."
Blanche did not say what evidence agents had of wrongdoing by the university. It was unclear whether he was accusing the school itself of "terrorism crimes" or saying that people involved in the protests had committed such crimes.
The Associated Press left messages seeking comment from the university about Blanche's accusations on Friday.
In a note to the school community following the searches on Thursday night, interim university president Katrina Armstrong said the school was "committed to upholding the law". She described herself as "heartbroken" that federal agents had been on campus searching student rooms.
"I understand the immense stress our community is under," Armstrong wrote. "Despite the unprecedented challenges, Columbia University will remain a place where the pursuit of knowledge is cherished and fiercely protected, where the rule of law and due process is respected and never taken for granted, and where all members of our community are valued and able to thrive."
Columbia has come under immense pressure from the Trump administration in recent weeks, with the US government cancelling USD 400 million in federal grants and contracts to the school, much of it for medical research, as punishment for not cracking down harder on students and faculty who criticised Israel's military action in Gaza during large protests last spring.
President Donald Trump and other officials have accused the protesters as being "pro-Hamas", referring to the militant group that attacked Israel on October 7, 2023.
The administration threatened to permanently end federal funding to the Ivy League school unless it took a variety of steps, including changing its admissions process and ceding faculty control of its Middle Eastern, South Asian, and African Studies Department to a receiver for five years.
It also demanded that the school ban people from wearing masks on campus, change how it recruits international students, adopt a new definition of antisemitism, and abolish its student disciplinary process.
Students and faculty who participated in last year's protests at Columbia have insisted that criticising Israel and advocating for Palestinian rights is not antisemitic. Some Jewish students and faculty, though, complained that the anti-Israel rhetoric made them feel unsafe.
Columbia University's campus has been in crisis since the arrest on Saturday of Mahmoud Khalil, a Palestinian activist who helped lead last spring's protests.
The Trump administration said on Friday it had revoked the visa of Ranjani Srinivasan, an Indian citizen and doctoral student at Columbia, for "advocating for violence and terrorism".
Srinivasan opted to "self-deport" on Tuesday, the department said. Officials did not say what evidence they had that Srinivasan had advocated violence.
The woman who was arrested in Newark, Leqaa Kordia, was charged with failing to leave the US after her visa expired. Columbia said it had no record of Kordia ever being a student there, or being arrested on the campus. However, there were numerous protests and arrests in the streets outside of the university at the same time.
Kordia had previously received a student visa, but it was terminated in 2022 for "lack of attendance", the department said. She is being held in an immigration detention centre in Alvarado, Texas, according to a government database.
Secretary of State Marco Rubio told reporters on Friday the Trump administration is expecting to revoke more student visas in the coming days.