Hundreds of workers at a Foxconn factory in Chengdu, China, have been arrested after a clash with security staff.
According to reports from Taiwan-based Want China Times (WCT), the clashes erupted on Monday night after protests against security workers.
Foxconn, the world's largest electronics maker, employs up to 120,000 people at the Chengdu plant, which mainly makes LCD displays.
According to WCT the riot broke out at male dorm, and the police were called in to arrest those causing the disturbance.
Up to 1,000 workers joined the clash, WCT said, throwing bins, chairs, pots, bottles and even fireworks from buildings down to the ground. The riot was eventually ended after two hours, when hundreds of police arrived at the site.
It was not possible for the Huffington Post UK to independently verify the reports.
The company, which makes products for companies including Apple, has been the focus on intense criticism over its working conditions.
A recent Students and Scholars Against Corporate Misbehaviour report said that intimidation and labour violations "remain the norm" despite efforts by Apple and other companies to improve conditions and drive down overtime.
Up to 20 or 30 workers can share just two or three room apartments, the report said and many workers are still forced to stand.
Last year an explosion at a Foxconn plant in Chengdu killed three people working on an iPad 2 production line.
"We want everyone to know what we are doing, and we hope that people copy. We've put a tonne of effort into taking overtime down," Apple CEO Tim Cook said recently.