Student protests over the Israel-Hamas war have popped up on an increasing number of college campuses following last week's arrest of more than 100 demonstrators at Columbia University.

The students are calling for universities to separate themselves from any companies that are advancing Israel’s military efforts in Gaza — and in some cases from Israel itself.

Protests on many campuses have been orchestrated by coalitions of student groups. The groups largely act independently, though students say they’re inspired by peers at other universities.

Pro-Palestinian student protesters set up a tent encampment at the Ivy League Columbia University in New York. Police first tried to clear the encampment on April 18, when they arrested more than 100 protesters. But the move backfired, inspiring students across the country and motivating protesters at Columbia to regroup.

Students said Friday afternoon that they had reached an impasse with administrators and intended to continue their encampment until their demands are met. Columbia officials had earlier said that negotiations were showing progress.

Hundreds of counterprotesters gathered on the streets outside Columbia on Friday morning, many holding Israeli flags and chanting for the hostages being held by Hamas and other militants to be released.

The university said in a statement Saturday night that students and administrators had engaged in negotiations.

Police in riot gear cleared an encampment on the campus of Northeastern University in Massachusetts on Saturday. State police said about 102 protesters were arrested and will be charged with trespassing and disorderly conduct. Protesters said they were given about 15 minutes to disperse before being arrested.

The University of Southern California said on Saturday it had temporarily closed its University Park Campus to nonresidents.

Joel Curran, senior vice president of communications, said in a statement that USC property was vandalized by members of a group “that has continued to illegally camp on our campus,” as well as disrupting operations and harrassing students and others.

Students declined numerous attempts by university President Carol Folt to meet, and the administration hopes for “a more reasonable response Sunday before we are forced to take further action,” Curran said.

The Los Angeles Police Department said more than 90 people were arrested Wednesday night on charges of trespassing during a protest at the university. One person was arrested on a charge of assault with a deadly weapon. There were no reports of injuries.

The university said Wednesday that it had closed campus and police would arrest people who did not leave.

In her first public statement in nearly two weeks, President Carol Folt in a statement late Friday — the last day of classes — condemned the protests while imploring the campus community to find common ground and ways to support each other.

Police clashed with protesters at Ohio State University in Columbus, just hours after they gathered Thursday evening. Those who refused to leave after warnings were arrested and charged with criminal trespass, said university spokesperson Benjamin Johnson, citing rules barring overnight events. Of 36 people arrested, Johnson said Friday that 16 were students and 20 were not affiliated with the university.

About 50 students at George Washington University in Washington, D.C., set up a tent encampment on the school’s University Yard on Thursday. Later in the day, a group of Georgetown University students and professors staged their own protest walkout and marched to the George Washington campus to join them. The protesters are demanding that the university divest from Israel and lift a suspension against a prominent pro-Palestinian student group.

The university said the protesters must remove tents and disperse by 7 p.m.

Northwestern University in Chicago, Ill., changed its student code of conduct Thursday morning to bar tents on its suburban Chicago campus as student activists set up an encampment.

University President Michael Schill issued an email saying the university had enacted an “interim addendum” to its student code to bar tents, among other things, and warned of disciplinary actions including suspension, expulsion and criminal charges.

“The goal of this addendum is to balance the right to peacefully demonstrate with our goal to protect our community, to avoid disruptions to instruction and to ensure university operations can continue unabated,” Schilling said.

The University of Pennsylvania interim President J. Larry Jameson called late Friday for an encampment of protesters on the west Philadelphia campus to be disbanded, saying it violated the university’s facilities policies.

The “harassing and intimidating comments and actions” by some protesters violate the school’s open expression guidelines as well as state and federal law, Jameson said, and vandalism of a statue with antisemitic graffiti was “especially reprehensible and will be investigated as a hate crime.”

“I am deeply saddened and troubled that our many efforts to respectfully engage in discourse, support open expression, and create a community that is free of hate and inclusive for everyone have been ignored by those who choose to disrupt and intimidate,” he said.

Failure to disband the encampment immediately and to adhere to Penn’s policies will result in sanctions consistent with our due process procedures as they apply to students, faculty, and staff, Jameson said.

The university’s chapter of the American Association of University Professors responded by urging the administration not to “escalate the situation” or “violate the rights of students and faculty.”