The new school year is still days away, but student protesters have already made a noisy return to Columbia University's New York campus, the epicenter of a pro-Palestinian protest movement that spread to schools around the world this spring.

Blowing whistles and banging drums, pots and pans and the iron railings of the closed campus gates, about 50 protesters marched on the sidewalk on Sunday evening and bellowed pro-Palestinian chants. A New York Police Department surveillance drone hovered over their heads.

Inside the gates, more than 1,000 new Columbia undergraduates had gathered for a convocation ceremony. Dr. Katrina Armstrong, Columbia's new interim president, was able to make herself heard over the protesters' din, describing to the new students her vision of the campus as a place of open debate where no one feels excluded.

Columbia administrators are hoping to avoid a repeat of the protests that roiled the university earlier this year, which culminated with hundreds of armed police officers sweeping the campus in April to arrest more than 30 student protesters who had barricaded themselves inside an academic building.

Since the spring, college administrators across the U.S. and beyond have grappled with tent encampments inspired by the Columbia protests spreading to their own campuses, followed by pro-Israel counterprotests. Some administrators also called in police; a minority have reached agreements over demands to sever financial ties with Israel.

"Effectively managing protests and demonstrations allows us to advance our educational and research missions while enabling free speech and debate," Armstrong, the dean of Columbia's medical school, wrote in a campus-wide email last week.

She has been interim leader since Minouche Shafik resigned as president earlier this month after facing criticism over handling of the protests, including a vote of no confidence by Arts and Sciences faculty angered by her decision to call in police to arrest students.

The pro-Palestinian protests have been led by Columbia University Apartheid Divest (CUAD), a coalition of student groups demanding the school end its investments in weapons manufacturers and other companies that support Israel's military occupation of Palestinian territories.

Over the summer, mediators had little success trying to revive negotiations between Columbia administration and CUAD, according to Mahmoud Khalil, a Palestinian graduate student who is one of the main negotiators on behalf of CUAD.

"The university should actually deal with the students as students, not as a threat to Columbia and the Columbia brand," he said. Columbia declined requests to interview administration officials and a spokesperson declined to answer questions about the talks with CUAD.