An Amazon.com Inc. warehouse worker in Shakopee, Minnesota, has accused the company of retaliating against her for protesting what she says are unsafe working conditions during the pandemic.

In a letter to Minnesota Attorney General Keith Ellison, Hibaq Mohamed said managers were demanding that she account for time away from her workstation -- including increments of less than three minutes. Mohamed said she is being singled out for her activism and that she is now one warning away from termination.

“I worked at Amazon for nearly four years with a very clean record and just one or two warnings I know of in that entire time,” she wrote in the July 13 letter, which was reviewed by Bloomberg. “Amazon managers have targeted me and openly harassed me before, but increasingly during the pandemic.”

Mohamed is the latest employee activist to accuse Amazon of retaliation. This year, the company has fired four employees who criticized the company for its treatment of workers. The termination of Chris Smalls, who led a demonstration at a warehouse in Staten Island, triggered an investigation by New York Attorney General Letitia James, who called his firing “immoral and inhumane.” Amazon has said all four were terminated for violating company policy.

Responding to Mohamed’s account, an Amazon spokeswoman said: “While we have not seen the formal complaint, the allegations described are not true. We do not tolerate any kind of discrimination in the workplace and we support every employee’s right to criticize their employer, but that doesn’t come with blanket immunity to ignore internal policies.”

Ellison’s office didn’t respond to requests for comment.

While Amazon (AMZN) earmarked $800 million in the first half of the year for safety measures including masks, sanitizer and temperature checks, workers continue to protest what they say are unsafe working conditions.

Mohamed has made no secret of her own activism and has been quoted in multiple media outlets accusing her employer of failing to protect workers. She led a video conference protest on June 24, during which she and other workers described concerns about getting sick and bringing the virus home to relatives. The protest was posted to Facebook, where it attracted 18,000 views.

Less than two weeks later, on July 5, warehouse managers warned Mohamed that she’d accumulated too much “time off task,” she said. Amazon monitors productivity, and employees must explain why they’ve been away from their workstations for more than 30 minutes per shift.

Mohamed said that in several cases she was either sanitizing her workstation, per the company’s Covid-19 policy, or visiting the restroom while obeying social-distancing requirements. In other instances, Mohamed said she was asked to account for “absurd one or two or three minute blocks of time throughout the day. Nobody could possibly remember those.”

What really caught her attention, Mohamed wrote, was that some of the times she was supposedly “off task” happened before her shift began. “That was the first sign to me that this was completely illegitimate,” she wrote.