Foxconn employees on the assembly line in Longhua, Shenzhen, China. The company reportedly employed students working overtime at its iPhone factory in Zhengzhou.

Apple supplier Foxconn has been employing students illegally work overtime to help assemble the iPhone X, the Financial Times reported Tuesday.

Six high school students told the Financial Times they would usually work 11-hour shifts to help manufacture Apple's flagship phone at a factory in Zhengzhou, China. The long hours breach Chinese laws regarding student interns.

The report said the six students interviewed were among a group of 3,000 students from Zhengzhou Urban Rail Transit School. The high schoolers said they had been sent to work at a local factory run by Taiwan-based supplier Hon Hai Precision Industry — better known as Foxconn — in September.

Apple, in a statement, said that it took action once it discovered the students were working overtime.

During the course of a recent audit, we discovered instances of student interns working overtime at a supplier facility in China. We've confirmed the students worked voluntarily, were compensated and provided benefits, but they should not have been allowed to work overtime. At this facility, student intern programs are short term and account for a very small percentage of the workforce. When we found that some students were allowed to work overtime, we took prompt action. A team of specialists are on site at the facility working with the management on systems to ensure the appropriate standards are adhered to.

Read the full article at the Financial Times.

Clarification: This story has been updated to clarify the fact that it was the fact that the students were working overtime was illegal, not the fact that they were students.