SANTA CRUZ, California (AP) — Graduate students at the University of California, Santa Cruz walked off their jobs and went on strike Monday, the first campus to do so as part of a systemwide protest against a public university they say has violated the speech rights of pro-Palestinian advocates.

United Auto Workers Local 4811 represents 48,000 graduate students who work as teaching assistants, tutors, researchers and other academic workers on the 10-campus UC system. Organizers said the campuses will not strike all at once, opting instead for rolling strikes among the campuses.

Organizers are protesting the administration’s response to pro-Palestinian encampments, including arrests of protesters at the Los Angeles, San Diego and Irvine campuses. They say the actions constitute an unfair labor practice.

“The ball is in UC’s court — and the first step they need to take is dropping all criminal and disciplinary proceedings against our colleagues,” Rafael Jaime, president of UAW 4811, said in a statement.

The administration says the strike is unlawful and a violation of the union’s contract with UC, which prohibits work stoppages, Lori Kletzer, campus provost and executive vice chancellor, said in a statement.

A rally is planned for noon at the main entrance of UC Santa Cruz.