Three Columbia University deans, who engaged in what the school's administration called troubling text message exchanges that touched on "ancient antisemitic tropes," have resigned, a university spokesperson said late on Thursday.

Cristen Kromm, former dean of undergraduate student life; Matthew Patashnick, former associate dean for student and family support; and Susan Chang-Kim, former vice dean and chief administrative officer, were earlier placed on leave, opens new tab as an investigation proceeded.

The message exchanges took place during an event on campus titled "Jewish Life on Campus: Past, Present, and Future" and followed weeks of protests at Columbia and other campuses around the country over Israel's war in Gaza, the university administration said in July.

"This incident revealed behaviour and sentiments that were not only unprofessional but also, disturbingly touched on ancient antisemitic tropes," the university said in July.

The three deans who resigned could not be contacted. The university spokesperson who confirmed their resignation did not provide further details.

The United States has seen months of protests over U.S. support for Israel's war in Gaza which has killed about 40,000 Palestinians, according to the local health ministry, while also displacing nearly the entire population of 2.3 million and causing a hunger crisis.

The latest bloodshed in the decades-old Israeli-Palestinian conflict was triggered on Oct. 7 when Palestinian Islamist group Hamas, which governed Gaza, attacked Israel, killing 1,200 and taking about 250 hostages, according to Israeli tallies.

Israel's assault on Gaza has also led to genocide allegations at the World Court. Israel denies those allegations and in turn, accuses Hamas of seeking genocide against Israel.

Campus demonstrators have demanded an end to the war, a halt to U.S. military support to Israel and a divestment by universities in companies that support Israel's occupation of Palestinian territories.

There have been allegations of antisemitic and Islamophobic rhetoric in some protests and counterprotests.

Columbia itself became a centre of protests where students set up encampments and police made violent arrests.