A strike by Starbucks workers in the US could escalate Christmas sales

A strike by Starbucks employees has spread to several cities, including New York, a union representing more than 10,000 baristas in the US has announced.

Reuters reported that the strike was triggered by an impasse in negotiations between Starbucks and the union over pay, staffing and scheduling issues. The five-day strike, which began last Friday and initially shut down some stores in Los Angeles, Chicago and Seattle, has spread to New Jersey, New York City, Philadelphia and St. Louis.

Starbucks said the strike had a limited impact on its operations, with only a small number of stores affected. However, the strike has spread to 10 cities, including Columbus, Denver and Pittsburgh, Ohio. Because of the holiday sales season, the strike could hurt Starbucks' Christmas results.

The United Workers union, which represents baristas, is demanding that the company immediately raise the minimum wage for hourly workers by 64 percent and add up to 77 percent over a three-year contract. In response, Starbucks called the demands "unsustainable."

Unite warned that the strike could spread to "hundreds of stores" in the run-up to Christmas. Starbucks operates more than 11,000 stores in the United States and employs about 200,000 people.

Starbucks has been negotiating with the union since April, and despite more than eight meetings and 30 agreements, the two sides have failed to reach an agreement on key issues.