Foxconn Technology Group, which makes devices for companies such as Apple, Sony and HP, on Monday shut one of its Chinese plants after a scuffle snow-balled into a violent riot.
Foxconn closed a factory at Taiyuan in Chinas Shanxi province after a fight broke out among as many as 2,000 workers, leaving 40 people injured.
A few of the company's employees were also reportedly arrested.
The fight between rival worker groups broke out in a dormitory at about 11 p.m. last night and escalated before security and police brought the situation under control, reports said.
The cause of the brawl was not immediately known.
"The cause of this dispute is under investigation by local authorities and we are working closely with them in this process, but it appears not to have been work-related," Foxconn said in a statement.
The Taiyuan factory of Foxconn employs 79,000 people and makes electronics, components, and precision molding for devices, including mobile phones.
Foxconn has seen a few violent incidents at its Chinese plants in recent times amid allegations of poor working conditions.