Starbucks has fired seven employees who were leading an effort to unionize a Memphis, Tennessee, store.

The Seattle coffee giant said Tuesday that the employees violated company policy by reopening a store after closing time and inviting non-employees to come inside and move throughout the store, including behind the counter and in back rooms. The employees used the store to do an interview with a local television station about their unionizing effort.

But the employees who were fired say Starbucks was retaliating against them for their unionization efforts. They say they plan to file a complaint with the National Labor Relations Board.

“Most of these partners had never had a write-up or anything,” said Beto Sanchez, 25, one of the workers who was fired.

The dispute comes as a growing number of Starbucks stores across the country seek to unionize. Since December, when a store in Buffalo, New York, became the first Starbucks location to form a union in decades, 66 stores in 20 states have filed petitions with the labor board to hold union elections, according to Workers United, which is organizing Starbucks workers.

Starbucks opposes unionization, saying the company functions best when it can work directly with its employees. But the company said Tuesday’s firings were not related to the unionization effort, but to store safety and security.

Sanchez, who started working at the downtown Memphis store last April, said workers there were concerned about unsafe COVID policies, among other issues. Sanchez and several others announced the formation of a union organizing committee last month on Martin Luther King Jr. Day.

Sanchez said Starbucks rarely enforced the policies he was fired for violating. For example, he was told that he shouldn’t have been in the store’s back office when he wasn’t on duty. But he said off-duty employees are frequently in that area to check their schedules or access pay stubs.

Sanchez said he hopes to return to work at Starbucks after the NLRB considers his case.

Michael Schoenfeld, an attorney for Workers United who is working with Sanchez, said Starbucks is selectively enforcing policies in order to discourage employees from forming a union.