Workers hoping to unionize Starbucks stores in the U.S. have won a preliminary victory before the National Labor Relations Board.

The board said employees at three separate Starbucks stores in Buffalo, New York, can hold union elections in November in a new ruling. The board rejected Starbucks' attempt to hold a single vote with 20 stores in the region.

If the effort is successful, the stores would be the first of Starbucks' 8,000 company-owned U.S. stores to unionize. The Seattle coffee giant opposes the unionization effort.

Starbucks said Thursday evening that it had just received the ruling and was evaluating its options. The company reported record fiscal fourth quarter revenue of $8.1 billion earlier Thursday and had announced a $1 billion effort to raise U.S. workers' pay.

"Our storied success has come from our working directly together as partners, without a third party between us," Starbucks said Thursday in a statement. "We remain focused on supporting our partners as well as maintaining open, transparent and direct conversations throughout the process."

The NLRB said the union elections will be held by mail-in ballot between Nov. 10 and Dec. 8. The NLRB will count the ballots on Dec. 9.

There are about 128 employees at the three stores that will vote, according to the NLRB decision.

"It's been disappointing to see Starbucks working overtime to try to stop us from organizing, but today's decision is a big win and soon we're going to have an even bigger victory when we vote our union in," said Michelle Eisen, an 11-year veteran of Starbucks in Buffalo and a member of Starbucks Workers United, the union organizing group.

Starbucks Workers United has the backing of the broader Workers United union, which represents 86,000 U.S. and Canadian workers in food service, textiles and other industries. Workers United is an affiliate of the Service Employees International Union.

The Starbucks unionization effort comes amid a broader wave of union activity around the U.S. More than 10,000 Deere & Co. workers went on strike earlier this month after the United Auto Workers rejected a contract offer, while 1,400 workers walked off the job at Kellogg Co.'s U.S. cereal plants.

Meanwhile, Amazon workers in New York are seeking to hold a union vote. Amazon workers in Alabama overwhelmingly rejected an effort to form a union there in April.