Student protesters march round their encampment on the Columbia University campus on Monday. Columbia began suspending students after activists defied a deadline. STEFAN JEREMIAH — THE ASSOCIATED PRESS.

By CEDAR ATTANASIO, JAKE OFFENHARTZ AND JONATHAN MATTISE | THE ASSOCIATED PRESS

NEW YORK >> Colleges around the U.S. implored pro-Palestinian student protesters to clear out tent encampments with rising levels of urgency Monday, as police made more arrests at the University of Texas and Columbia University said it was beginning to suspend students who defied an ultimatum to leave the encampment there by an afternoon deadline.

Protesters who returned to the University of Texas at Austin on Monday were quickly greeted by dozens of law enforcement officers, many in riot gear. Six protesters were quickly arrested and others were taken into custody one by one. Officers used pepper spray after a group of protesters blocked the path of a police van carrying demonstrators who were arrested. The crowd backed away but continued to block the exit from campus. Officers then used two flash bang explosives to clear a path so the van could leave.

Republican Gov. Greg Abbott reposted on social media video of troopers arriving on the 50,000-student campus. “No encampments will be allowed. Instead, arrests are being made,” Abbott said.

Just last week, hundreds of police — including some on horseback and holding batons — pushed into protesters at the university, sending some tumbling into the street. Officers made 34 arrests at the behest of the university and Abbott, according to the state Department of Public Safety.

In New York, Columbia began suspending students after activists defied a 2 p.m. deadline to respond to the ultimatum, according to school spokesperson Ben Chang.

Instead, the students continued chanting, clapping and drumming from the encampment of more than 300 people. No officials appeared to enter the encampment, with at least 120 tents staying up as the deadline passed. Hundreds of protesters marched around the quad, weaving around piles of temporary flooring and green carpeting meant for graduation ceremonies. A handful of counter-demonstrators waved Israeli flags, and one held a sign reading, “Where are the anti-Hamas chants?”

The notice sent by the Ivy League university in Manhattan said that if protesters left by the deadline and signed a form committing to abide by university policies through June 2025 or an earlier graduation, they could finish the semester in good standing. If not, the letter said, they would be suspended, pending further investigation.

College classes are wrapping up for the semester, and campuses are preparing for graduation ceremonies, giving schools an extra incentive to clear encampments. The University of Southern California canceled its main graduation ceremony.

But students have dug in their heels at some high-profile universities, with standoffs also continuing at Harvard, the University of Pennsylvania, Yale and others.