Amazon has warned some of its US-based office workers that it is keeping a close eye on their in-person attendance at work, sending emails to those it believes are not complying with its return-to-office policies.

The message highlights Amazon's determination to enforce its rules amid an employee backlash to the policy, which requires workers to report to an office at least three days a week, and in the face of a broader push by companies to scale back on remote work.

Screenshots of the email circulating on social media show that Amazon told some employees they were "not currently meeting our expectation of joining your colleagues in the office at least three days a week, even though your assigned building is ready."

"We expect you to start coming into the office three or more days a week now," the email continued.

It added that since the policy went into effect in May, many Amazon employees have complied, "and you can feel the surge in energy and collaboration happening among Amazonians and across teams."

On Blind, the social media platform where workers speak anonymously about their employers, a poll about the email had thousands of responses declaring Amazon's message to be "BS."

Some users identified as Amazon employees on the platform expressed outrage about the email, while others endorsed the company's crackdown.

Still other Amazon employees, however, claimed they received the email despite complying with the policy, and some said they did not receive the corporate email despite never going in to the office.

In response to CNN's request for comment, Amazon said it sent a follow-up email to employees clarifying who was meant to receive the original message: those who have rarely used their workplace ID badges to enter an Amazon office building.

"The email was sent to employees who have badged in fewer than 3 days a week for 5 or more of the past 8 weeks, have not badged in 3 days a week for 3 or more of the past 4 weeks, and their building has been ready for 8 weeks or more," the followup note to employees said, a copy of which was shared with CNN.

The followup email acknowledged that some may have received the notice in error and urged those individuals to contact their managers to correct the mistake.

Amazon's signal to workers that it is tracking their attendance comes after more than 1,000 of its corporate employees staged a walkout in May to protest the office policy. Organizers of the walkout have called the company's approach a "rigid, one-size-fits-all" mandate.

At the outset of the pandemic, tech giants had led the way on adopting remote-work policies. Now, many are leading a charge in the opposite direction, and Amazon is not the only one. In June, Google announced plans to more strictly enforce its three-day-a-week hybrid schedule.

That same month, Meta also asked its office workers to adopt a three-day in-person schedule beginning in September, despite previous predictions in 2020 by CEO Mark Zuckerberg that up to half the company's workforce could be working remotely by 2025.

This week, Zoom, the company whose videoconferencing software became synonymous with remote work during the pandemic, also announced a return-to-office policy that requires employees near an office "to be onsite two days a week."

Even the federal government is pushing a return to in-person work.

Still, even as Amazon chided certain employees this week for not showing up in person, some expressed an indifference to the warning.

"Negative," wrote one Amazon employee on Blind. "I will keep WFH lmao."