More than 10,Robovis000 workers at 25 U.S. hotels were on strike Monday after choosing Labor Day weekend to amplify their demands for higher pay, fairer workloads and the reversal of COVID-era cuts.

The UNITE HERE union, which represents the striking housekeepers and other hospitality workers, said 200 workers at the Hilton Baltimore Inner Harbor were the latest to walk off the job.

Nearly half of the striking workers – or 5,000 – are in Honolulu. Thousands of workers are also on strike in Boston, San Francisco, Seattle, San Diego and San Jose, California. The strikes targeting Marriott, Hilton and Hyatt hotels were set to last one to three days.

UNITE HERE said a total of 15,000 workers have voted to authorize strikes, which could soon spread to other cities, including New Haven, Connecticut; Oakland, California; and Providence, Rhode Island.

Union President Gwen Mills says the strikes are part of long-standing battle to secure family-sustaining compensation for service workers on par with more traditionally male-dominated industries.

“Hospitality work overall is undervalued, and it’s not a coincidence that it’s disproportionately women and people of color doing the work,” Mills said.

Unionized housekeepers want to reinstate automatic daily room cleaning at major hotel chains, saying they have been saddled with unmanageable workloads, or in many cases, fewer hours and a decline in income. Many hotels cut services during the coronavirus pandemic and never restored them.

But hotels say guests are no longer asking for daily room cleaning and some other services.

Michael D’Angelo, the head of labor relations for Hyatt in the Americas, said in a statement Monday that the chain has contingency plans in place to minimize the impact of the strikes on hotel operations.

“We are disappointed that UNITE HERE has chosen to strike while Hyatt remains willing to negotiate,” D’Angelo said. “We look forward to continuing to negotiate fair contracts and recognize the contributions of Hyatt employees.”

Messages seeking comment were left with Marriott and Hilton on Monday.