Amazon is prohibiting off-duty warehouse workers from entering its buildings in an alleged effort to combat unionization.

According to AP News, Amazon informed its employees via the company’s internal app. Employees are not allowed to come into Amazon’s buildings on their days off or before or after their shifts.

Amazon has a well-established reputation for aggressively combating organization efforts. The company has been accused of trying to intimidate workers during previous organization attempts and has even resorted to using Pinkerton detectives to keep tabs on such efforts.

The company denies its latest move has anything to do with combatting organization efforts, insisting it’s more about employee safety.

“There’s nothing more important than the safety of our employees and the physical security of our buildings,” Amazon spokesperson Kelly Nantel told AP News. “This policy regarding building access applies to building interiors and working areas. It does not limit employee access to non-working areas outside of our facilities.”

Employees aren’t buying it, believing the measure is a direct threat to their efforts.

“On our days off, we come to work and we engage our co-workers in the break rooms,” said Rev. Ryan Brown, an Amazon warehouse worker in Garner, North Carolina, who is working to organize his fellow workers.

“This was a direct response to that, to try to stop organizing by any means necessary,” Brown said.