Foxconn Technology- a major supplier for Apple products has halted production at a plant in northern China after a fight broke out among workers.Foxconn confirmed that a “personal dispute” escalated into an incident involving about 2,000 workers, injuring 40 of them.
Police later dealt with the situation near the facility in Taiyuan, which employs about 79,000 workers.
Foxconn has previously been accused of having poor conditions for its workers- with 20 workers committing suicide in the past few years.
Foxconn said the incident started on Sunday at about 23:00 local time (15:00 GMT) in a dormitory near the Taiyuan manufacturing facility in Shanxi province.
Internet users in China posted pictures on microblog sites which they said had been taken at the scene showing windows of nearby shops smashed and police vehicles overturned.
Some photos showed police and paramilitary officers in riot gear being deployed to the scene.
About 40 people were taken to hospital and a number of individuals have been arrested, the company said.
A senior government official from Taiyuan City was quoted by the official Xinhua news agency as saying that three of the injured people were in a serious condition.
The Xinhua agency reported that the dispute had been brought under control by 5,000 policemen by 09:00 local time on Monday.
Unverified messages on the Twitter-like social network Weibo suggested that violence from security guards may have sparked the unrest.
One said that four or five security guards had beaten a worker almost to death, while another said that rioting workers had been targeting security guards who had earlier beaten some of their colleagues.
Earlier in the year a fight broke out in a restaurant at a Foxconn plant involving about 100 workers.