Apple’s longtime manufacturing partner Foxconn has reportedly been employing students to work overtime illegally at its factories for assembling the iPhone X. The Financial Times has heard from six high school students in China who told the scribe that they regularly work 11-hour days to assemble Apple’s new flagship device. Such long work days are illegal for student interns as per China’s laws.

The students were reportedly 17 to 19 years old. They were told that they had to work at the Foxconn factory for three months before they could graduate. The students that the FT spoke to all volunteered to work overtime and they were paid for it illegally.

One student even told the Financial Times that they were forced to work at the Foxconn factory and that the work they were doing wasn’t related to their studies. That student claimed to have assembled as many as 1,200 cameras for the iPhone X every single day.

Apple and Foxconn have both said that the students were not “forced” to work beyond the hourly limits laid down by law. They have acknowledged that some cases of student interns working overtime do exist and they’re looking into measures to ensure that this doesn’t happen again.

Foxconn worked with local governments and vocational institutions to organize the internship program. It has agreed that the overtime work violated its own policy that prohibits students from working more than 40 hours a week.

“We’ve confirmed the students worked voluntarily, were compensated and provided benefits,” Apple said, adding that they “should not have been allowed to work overtime.”

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