U.S. Sen. Kamala Harris, D-Calif., is heeding a boycott call by striking University of California employees and announced Monday that she will not be commencement speaker at UC Berkeley ceremonies.

Harris said she "regretfully" won't attend Saturday's spring commencement due to the labor dispute and the call for a university-wide speaker boycott. Instead, UC Berkeley Chancellor Carol Christ will deliver the keynote address.

Harris says she wishes the estimated 5,800 students "success for the future."

Thousands of UC custodians, security guards, gardeners and other service workers began a three-day walkout on Monday to address gender pay inequalities and demand higher wages.

The Associated Press reported that officials at UC Davis Medical Center were forced to reschedule more than 100 cancer exams and 150 radiology exams.

The American Federation of State, County and Municipal Employees Local 3299 called for the strike, according to The San Francisco Chronicle. The union includes 25,000 service workers.

The report said medical workers sympathetic to the strikers are set to join walkouts set for the next few days. Essential patient care will be provided, the report said. Hundreds of surgeries, however, were rescheduled.

Claire Doan, a spokesman from the UC system, said the service workers are already paid at or above the market rate and now demanding an almost 20 percent pay increase over three years.

"A disruptive demonstration will change neither UC's economic situation nor the university's position on AFSCME's unreasonable demands," Doan said.

The Associated Press contributed to this report