Between classes, when throngs of students stream into and out of Columbia University’s campus, the security lines can back up like a TSA checkpoint. There’s a switch-back path of metal fencing that leads into a white tent, where two sets of guards check and then swipe campus ID cards before letting students in and out.

Columbia University says it has expelled or suspended some students who took over a campus building during pro-Palestinian protests last spring and temporarily revoked the diplomas of some students who have since graduated.

The university’s escalation in disciplinary action comes as campus tensions are at a recent high following the detention of Mahmoud Khalil.

In an email, Interim President Katrina Armstrong wrote that she was “heartbroken” to inform students and faculty of the federal agents’ visit. The students were not arrested or

Mahmoud Kahlil, a Columbia University student who protested Israel’s war in Gaza, sued to block the turnover of disciplinary records to a U.S. House committee.

New York City police arrested 98 people during protests against the detainment of Columbia University graduate student Mahmoud Khalil, 30.