May 7 (UPI) -- Thousands of medical workers in the statewide University of California higher education system started a three-day strike Monday, to highlight what they say is a growing wage disparity.
Picketers gathered early Monday at the University of California, Los Angeles Medical Center, and at medical facilities elsewhere across the state.
The total walkout could involve more than 50,000 workers, union officials said.
Three unions that represent the university system are involved in the labor dispute -- led by the American Federation of State, County and Municipal Employees, which represents medical workers, security guards, truck drivers and other technical specialists.
"The big picture here is that there's growing inequality at the University of California, and we're going out because they have not even attempted to address it," AFSCME Local 3299 President Kathryn Lybarger told NBC News.
Surgeries for the next three days at the UCLA hospital have been rescheduled due to the strike, KCBS-TV reported, and more postponements are expected to follow statewide.
The unions cite as reasons for the strike a growing income gap, higher healthcare premiums, outsourcing of low-paying service worker jobs and a union report that says women and minorities are paid less than white men in the University of California system.
University officials deny pay is based on gender or race, and said it cannot dedicate tax money to the wage increases the unions are demanding. Both sides have been negotiating the issue for more than a year.
The UC system said workers are already paid at or above prevailing rates, and picketers' demand for a 6 percent raise is excessive.
"A strike is only hurting the union's own members who will lose pay for joining this ill-advised three-day walkout, while negatively affecting services to patients and students," a University of California spokesperson said. "A disruptive demonstration will change neither UC's economic situation nor the university's position on AFSCME's unreasonable demands."
California's Public Employment Relations Board and a state court each ruled last week the workers are legally entitled to strike.
Monday's strike follows a number of other protests by U.S. teachers. Educators in West Virginia, Kentucky, Oklahoma and Arizona have all walked out this year over the wage issue.