Foxconn, Apple’s main supplier in Asia, has reportedly been employing students to illegally work overtime to assemble the iPhone X, due to the company struggling to keep up with production demands.

Six high school students, aged 17 to 19, have said they regularly work 11-hour days at a factory in Zhengzhou, China, which is illegal for student interns under Chinese law, according the Financial Times.  

One of the students said they were being forced to work there by their school, and the work has nothing to do with their education. She added that she is made to assemble up to 1,200 iPhone X cameras each day.

The students are said to part of a group of 3,000 from the Zhengzhou Urban Rail Transit School that were sent to work in the Chinese factory owned by the Taiwanese electronics manufacturer Hon Hai Precision Industry, which trades as Foxconn.

Apple and Foxconn have both acknowledged the problem and have said they are taking action. According to Foxconn, the internship programme is conducted in co-operation with the local government and vocational schools in China, though it stated that it prohibits student interns working more than 40 hours a week.

The iPhone X has faced a number of production issues throughout its making, with its release date being pushed back in the first place. In addition, last month, Apple was accused of relaxing its specifications for the Face ID feature in order to help factories push through more devices.