Workers at some Starbucks stores started a five-day strike Friday in three U.S. cities, including Chicago, to protest lack of progress in contract negotiations with the company. S

The strike, which began Friday in Los Angeles, Chicago and Starbucks’ hometown of Seattle, continued spreading to stores across the country over the weekend.

The walkouts in Los Angeles, Chicago and Seattle come after talks between the company and the workers’ union failed to produce an agreement on raises.