Bloomberg reports that China Labor Watch, a nonprofit organization, recently investigated two factories in China that manufacture goods for Ivanka Trump’s brand. Workers are allegedly forced to work a minimum of 12 1/2 hours per day, six days a week, which amounts to a monthly salary of just 2,500 yuan ($363). The group probed the two factories between May 2016 and April 2017.

Li Qiang, founder of New York-based China Labor Watch, told Bloomberg that workers at one of the factories are paid according to the number of pieces that they produce. The staff commonly works overtime to reach the target, Li said. But if quota isn’t met, the workers aren’t paid any extra. Some are reportedly paid less than $1 per hour, he added.

The labor rights group sent its findings in a letter to Ivanka Trump. While the First Daughter has yet to respond directly to the allegations, (she has stepped away from the brand in recent months to avoid conflicts of interest), Abigail Klem, president of the Ivanka Trump brand, told Bloomberg that it’s “impossible for us to respond to allegations, with no supporting evidence, concerning an unnamed factory.”

Klem also said that the company adheres to labor standards.

“Ivanka Trump HQ is committed to only working with licensees who maintain internationally recognized labor standards across their supply chains,” Klem told Bloomberg in an emailed statement. “Our licensees and their manufacturers, subcontractors and suppliers must comply with all applicable local and international labor laws, and the legal and ethical practices set forth in our vendor code of conduct.”

A spokesperson for the Ivanka Trump brand was not immediately available for comment when contacted by Fortune.