Starbucks baristas at locations in a dozen states have walked off the job as part of a holiday strike they say could spread to hundreds of stores by Tuesday unless the company ups its wage offer in contract negotiations that have been ongoing for the better part of the year.

Amazon delivery drivers and Starbucks baristas have expanded strikes in several U.S. cities before the holidays. The workers are demanding the companies recognize them as unionized employees or meet their demands for an inaugural labor contract.