More than 1,500 Marriott International Inc. employees went on strike in Boston Oct. 3, UNITE HERE Local 26 spokeswoman Nicki Morris said.

Seven hotels in Boston are affected by the strike, including the Ritz-Carlton Boston and the W Boston.

Marriott workers have been threatening to strike for the last few weeks in seven other cities: Detroit, Seattle, San Francisco, San Diego, San Jose, Calif., and on the Hawaiian Islands of Maui and Oahu.

The union and Marriott have been negotiating...