Colleges around the US have implored pro-Palestinian student protesters to clear out tent encampments with rising levels of urgency, including an ultimatum from Columbia University for students to sign a form and leave the encampment by the afternoon or face suspension.

College classes nationwide are wrapping up for the term, and campuses are preparing for graduation ceremonies.

The notice sent by Columbia to protesters in the encampment on Monday said that if they leave by the designated time and sign a form committing to abide by university policies through to June 2025 or an earlier graduation, they can finish the term in good standing.

If not, the letter said, they will be suspended, pending further investigation.

“We urge you to remove the encampment so that we do not deprive your fellow students, their families and friends of this momentous occasion,” the letter said, noting that exams are beginning and graduation is upcoming at the Ivy League university in New York City.

A spokesperson for Columbia confirmed the letter had gone out to students but declined to comment further.

Mahmoud Khalil, the lead negotiator on behalf of protesters, said university representatives began passing out the notices at the encampment shortly after 10am on Monday. He said discussions were ongoing about how to proceed.

Early protests at Columbia, where demonstrators set up tents in the centre of the campus, sparked pro-Palestinian demonstrations across the country.

Students and others have been sparring over the Israel-Hamas war and its mounting death toll. Many students are demanding their universities cut financial ties with Israel.

About 275 people were arrested on Saturday at various campuses including Indiana University at Bloomington, Arizona State University and Washington University in St Louis.

The number of arrests nationwide has passed 900 since New York police removed a pro-Palestinian protest encampment at Columbia and arrested more than 100 demonstrators on April 18.

The demonstrations at Columbia have led it to hold remote classes and set a series of deadlines for protesters to leave the encampment, which they have missed. The school said in an email to students that bringing back police “at this time” would be counterproductive.

The students and administrators have negotiated to end the disruptions, but the sides have not come to an agreement, university president Minouche Shafik said in a statement on Monday.

Protests were still active at a number of campuses. Near George Washington University, people at an encampment breached and dismantled the barriers on Monday morning used to secure University Yard, the university said in a statement. The yard had been closed since last week.

Protesters at Yale University set up a new encampment with dozens of tents on Sunday afternoon, nearly a week after police arrested nearly 50 demonstrators and cleared a similar camp.

At least one school, the University of Southern California, cancelled its main graduation ceremony this spring.

Protesters on both sides shouted and shoved each other during duelling demonstrations on Sunday at the University of California, Los Angeles.

The university stepped up security after “some physical altercations broke out among demonstrators”, said Mary Osako, vice chancellor for UCLA strategic communications. There were no reports of arrests or injuries.

The plight of students who have been arrested has become a central part of protests, with the students and a growing number of faculty demanding amnesty for protesters. At issue is whether the suspensions and legal records will follow students through their adult lives.