Police broke up a pro-Palestinian Arab encampment at the University of Michigan before dawn Tuesday, citing a threat to public safety, reported The Associated Press.

Officers wearing helmets with face shields cleared approximately 50 people from the Diag, known for decades as a site for campus protests. Video posted online showed police using what appeared to be an irritant to spray people, who were forced to retreat.

At least four people were arrested, which caused protesters to shift to the Washtenaw County jail where they marched outside in support of their allies, according to AP.

The campus encampment was set up on April 22, near the end of the school year and just before families began arriving for spring commencement. Posters taunting President Santa Ono and other officials were also displayed.

Earlier this month, a group of pro-Palestinian Arab protesters briefly interrupted the spring commencement ceremony at the University of Michigan.

Protesters have demanded that the school’s endowment stop investing in companies with ties to Israel. The university insists it has no direct investments and less than $15 million placed with funds that might include companies in Israel, less than 0.1% of the total endowment.

Pro-Palestinian Arab encampents have been set up at campuses across the US in recent weeks, as protests against the war in Gaza intensify.

Some of the anti-Israel encampments at universities have been taken down by police officers, while others have been cleared voluntarily following agreements with the administrations.

Last week, anti-Israel protesters were voluntarily taking down their tents in Harvard Yard, after university officials agreed to discuss their questions about the endowment.

Previously, LAPD and California Highway Patrol cleared an anti-Israel protest encampment on the UCLA campus, arresting 132 people.

Later, the Los Angeles Police Department removed a pro-Palestinian Arab encampment at the University of Southern California, pushing several dozen people out of the campus gates.

In another incident, police in riot gear cleared an anti-Israel encampment at the University of Chicago.

At Cornell University, meanwhile, the student encampment disbanded peacefully, with neither arrests being made nor a deal being reached with management.