About 5,000 police have been deployed to control a mass brawl among workers at a Foxconn plant in northern China.
Taiwan's Foxconn Technology Group, which assembles Apple iPhones and makes components for top global electronics companies, closed its Taiyuan plant in China after about 2,000 workers were involved in a brawl at a company dormitory.
It was not clear how long the shutdown would last at the plant, which employs about 79,000 people.
Police and company officials are investigating the cause of the disturbance.
Foxconn said the trouble started with a personal row that blew up into a brawl.
But some people posting messages on a microblog site said factory guards had beaten workers and that sparked the melee.
"The plant is closed today for investigation," Foxconn spokesman Louis Woo said.
An employee contacted by telephone said the closure could last two or three days.
Pictures from just outside the plant showed broken windows at a building by an entrance gate and a line of olive-coloured paramilitary police trucks parked inside the factory grounds.
The unrest is the latest in a string of incidents at plants run by Foxconn, the trading name of Hon Hai Precision Industry Co and the world's largest contract maker of electronic goods.
Drawing attention as a supplier and assembler for Apple products, the company has faced accusations of poor conditions and mistreatment of workers at its operations in China, where it employs about 1 million workers.
5,000 police sent to quell mass Foxconn brawl - ABC News (Australian Broadcasting Corporation)