Foxconn Technology Group, Apple’s iPhone assembler and component supplier for major global electronics firms, has halted production at its Taiyuan facility in China after a fight broke out among 2,000 employees.
According to the firm, the brawl has injured nearly 40 people.
Xinhua News Agency cited a statment from police as saying that the situation had been brought under control by 5,000 policemen and an initial investigation had found that the fighting had been a clash between workers from Shandong Province and Henan Province.
Foxconn revealed that the order was restored after four hours and several people were arrested.
Foxconn said the the trouble started from a personal row leading to the brawl. However other reports suggest it was factory security guards beating workers that led to the browl.
Foxconn spokesman Louis Woo told Reuters: "The plant is closed today for investigation."
Clients of Foxconn, which employs about 79,000 people, include Apple, Microsoft and Hewlett-Packard.
Earlier, Foxconn has been accused of poor working conditions and mistreatment of workers at its Chinese facilities. The company increased pay and agrred to limit hours after an auditor hired by Apple found Foxconn employees regularly were required to work over 60 hours per week.