Workers at an Amazon warehouse in San Francisco are on strike Thursday, joining six other delivery stations of the e-commerce company across the country. The Teamsters, who are seeking a labor agreement during a key shopping period,

Coordinated strikes ahead of Christmas in a handful of cities including San Francisco and New York see the Teamsters challenge the nation’s second-largest private employer.

Amazon delivery drivers and Starbucks baristas are on strike in a handful of U.S. cities as they seek to exert pressure on the two major companies to recognize them as unionized employees or to meet demands for an inaugural labor contract.