A contentious labor dispute between graduate-student workers and the University of California at Santa Cruz resulted in the arrest of 17 students this week, ratcheting up tensions as students refuse to end their strike without a pay increase.

Hundreds of graduate students have gathered on campus since Monday to demand a cost-of-living adjustment that would result in a raise of $1,412 a month. They say that amount would make it easier to afford housing in one of the most expensive rental markets in the country. But university administrators say their hands are tied because of a contract with the United Automobile Workers, the union that represents graduate students across all 10 campuses of the UC system.

Demonstrations have been tense from the outset. Students say the deployment of campus police in riot gear is intimidating and unnecessary for peaceful protests, and students have accused officers of using excessive force. University officials say several dangerous incidents have unfolded between picketers and vehicles at an intersection near campus, and officers are trying to keep everyone safe.

Tensions came to a head Wednesday when police tried to remove demonstrators occupying the intersection. Protesters locked arms and sat in the road at the main entrance of the campus for more than four hours, facing off with police, according to students and the university. The standoff ended with the arrest of 17 demonstrators for unlawful assembly and failure to disperse, university spokesman Scott Hernandez-Jason said.

“Officers repeatedly tried to de-escalate the situation and made clear that blocking this major roadway had to stop or it would lead to arrest,” Hernandez-Jason said in an email Thursday. “Failing to comply with an order to disperse and obstructing a roadway is extremely dangerous, and it is also against the law.”

Jane Komori, a doctoral student and strike organizer, said demonstrators knew their action could result in arrest, but she said police used excessive force in dragging them off the road. She said one student sustained a broken finger, while another received a gash on the head.

Hernandez-Jason said the university is aware of the “unsubstantiated rumors” of excessive force and encourages anyone who has a complaint about police conduct to submit it.

In a letter sent Wednesday to UAW Local 2865, the University of California’s chief operating officer, Rachael Nava, implored the union to bring the demonstrations to an end. Although the students are waging what’s known as a wildcat strike, meaning there was no sanctioned vote to take action, union leaders have asked the university to consider their demands.

Even though a new contract was ratified last year and expires in 2022, the university could add a provision to address the cost-of-living increase. Nava said the UC system is not interested in exploring that option or willing to reopen the collective bargaining agreement covering students.

The union contract yielded a 3 percent wage increase for graduate students who earn about $2,400 a month — before taxes — for nine months out of the year. Because the deal covers students across the UC system, there is no accounting for disparities in living expenses from one area to the next, Komori said.

She counts herself lucky to pay $600 a month in rent, sharing a room with a friend, in a house with three other occupants. It’s a tight squeeze and utility costs are high, but the 25-year-old said at least there isn’t much mold. Some of her colleagues have developed respiratory problems from living in apartments with black mold.

“Many of us spend 50 percent to 70 percent of our wages on rent,” Komori said. “It’s just become too difficult for most graduate students to survive in Santa Cruz … which is why things have escalated so quickly. It’s about the degree of desperation among graduate students here.”

Graduate workers initially launched a grade strike, withholding final grades for undergraduate students, in December to force the administration to negotiate a wage increase. The action resulted in many teaching assistants receiving reprimands.

Hernandez-Jason said the university is trying to address the lack of affordable housing, but a housing project that would have created 3,000 new beds on campus is being held up in the courts. Meanwhile, the university has announced a need-based annual housing supplement of $2,500 for doctoral students until more graduate housing becomes available. But students say the measure is insufficient and has no bearing on them being priced out of the rental market.