More than 1,000 unionized Starbucks workers are planning to strike at 65 U.S. stores starting Thursday.

The strike was scheduled to disrupt Starbucks’ Red Cup Day, which is typically one of the company’s busiest days of the year. Starbucks gives away free, reusable cups on that day to customers who buy a holiday drink.

The union working to organize Starbucks baristas says the striking workers are protesting a lack of progress in labor negotiations with the company.

Starbucks Workers United says the walkout will impact stores in 45 cities, including New York, Philadelphia, Minneapolis and Dallas. Starbucks says fewer than 4% of its U.S. stores are unionized, and most stores will be operating normally.

Starbucks workers gathered outside a Philadelphia location with signs like "Red Cup Rebellion" and chants including "No contracts, no coffee" and "Union Power"

AP video shot by Tassanee Vejpongsa