Hundreds of Chinese schoolchildren have unfairly — and often illegally — been drafted into working nighttime and overtime shifts to produce Amazon’s Alexa devices, a new investigation revealed.

Interviews The Guardian conducted with workers, as well as leaked documents from Amazon’s supplier Foxconn, show that many teens have been required to work nights in violation of China’s labor laws to produce the smart-speaker devices.

The teens, drafted from schools and technical colleges in and around the central-southern city of Hengyang, are classified as “interns,” and the factory pays their teachers to accompany them, according to the Thursday report.

Teachers are urged to coax students into accepting overtime work when they are unwilling to do so, the newspaper learned.

One of those students, a 17-year-old girl, told researchers she started work at the factory on the Amazon Echo production line late last month.

The computing student, whose job is to apply a protective film to about 3,000 Echo Dots each day, said her teacher initially informed her that she’d be working eight hours a day, five days a week, but now she is required to work 10 hours a day — including two hours of overtime — six days a week.

“I tried telling the manager of my line that I didn’t want to work overtime,” the student told researchers. “But the manager notified my teacher and the teacher said if I didn’t work overtime, I could not intern at Foxconn and that would affect my graduation and scholarship applications at the school.”

“I had no choice, I could only endure this,” she added.

Documents leaked by China Labor Watch and provided to The Guardian indicate that Foxconn managers need students to work overtime to meet production targets — and those who don’t are let go.

“Student interns who don’t work overtime will not only affect the production goal but also affect their willingness to work,” one document states. “Student interns need to work overtime.”

Another document explains that the students were recruited “to fulfill the shortage of the labor force and lower the cost of labor recruitment.”

“Low labor cost, can hire a large amount of labor at once, easier to reassign additional workers to other positions, strong ability to learn new things,” the document said.

In a statement issued to The Guardian, Foxconn, which also makes iPhones for Apple, admitted that the company had employed students illegally and is working to resolve the situation immediately.

“We have doubled the oversight and monitoring of the internship program with each relevant partner school to ensure that, under no circumstances, will interns [be] allowed to work overtime or nights,” the statement said. “There have been instances in the past where lax oversight on the part of the local management team has allowed this to happen and, while the impacted interns were paid the additional wages associated with these shifts, this is not acceptable and we have taken immediate steps to ensure it will not be repeated.”

Amazon told the paper that the company would not tolerate violations of its code of conduct — and regularly used independent auditors to monitor suppliers’ compliance and improvement.

“If we find violations, we take appropriate steps, including requesting immediate corrective action,” a company spokesperson said. “We are urgently investigating these allegations and addressing this with Foxconn at the most senior level. Additional teams of specialists arrived on-site yesterday to investigate, and we’ve initiated weekly audits of this issue.”