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

A five-day strike by Starbucks baristas had closed 59 stores as of Monday afternoon, according to the union organizing the workers.

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