Starbucks Workers United began an open-ended strike Thursday in at least 40 cities on Red Cup Day, one of the chain’s busiest sales days.

The union said the action involves more than 1,000 baristas across over 65 stores, following a vote to authorize the strike after negotiations with Starbucks failed to produce a collective bargaining agreement.

The strike comes at a critical time for Starbucks, coinciding with the busy holiday season, which typically drives a sales boost and is central to the company’s plan to improve U.S. performance under new CEO Brian Niccol.

The union is demanding better hours, higher wages, and the resolution of hundreds of unfair labor practice claims against the company. Active negotiations have stalled since late last year when talks broke down.

Starbucks and the union entered mediation in February, and barista delegates rejected the economic package Starbucks proposed in April.

Both sides have blamed each other for the impasse but say they remain ready to negotiate.

Union leaders say the action responds to stalled negotiations, more than two years after employees first voted to unionize in late 2021.

“We’re prepared to do whatever it takes,” said Jasmine Leli, a barista in Buffalo, New York, and one of the delegates representing the union in negotiations, in an interview last week.

“Starbucks not finalizing this union contract is failing its baristas and customers alike.”

However, Starbucks denied any wrongdoing and accused the union of walking away from negotiations.

“We’re disappointed that Workers United has called a strike instead of returning to the bargaining table,” company spokesperson Jaci Anderson said Wednesday.

She stated that “nearly all” Starbucks locations would remain open to serve customers despite the strike.