The fight, the cause of which is under investigation, erupted Sunday night at a privately managed dormitory near a Foxconn Technology Group factory in the northern city of Taiyuan, the company and Chinese police said. A police statement reported by the official Xinhua News Agency said 5,000 officers were dispatched to the scene.
The Taiwanese-owned company declined to say whether the factory is involved in iPhone production. It said the facility, which employs 79,000 people, will suspend work Monday and reopen Tuesday.
Foxconn makes iPhones and iPads for Apple Inc. and also assembles products for Microsoft Corp. and Hewlett-Packard Co. It is one of China's biggest employers, with some 1.2 million workers in factories in Taiyuan, the southern city of Shenzhen, in Chengdu in the west and in Zhengzhou in central China.
The unrest happens at a critical time for Apple. The fight started days after the launch of the latest iPhone model in the U.S. and eight other countries. The phone quickly sold out in most stores in the U.S. and Apple has a three to four-week backlog of online orders as it ramps up production to meet demand.
On Monday, Apple said it sold 5 million units of the new iPhone 5 in the first three days, less than analysts had expected. Its stock fell 1.4 percent to $690.50 in midday trading.
The fight in Taiyuan started at 11 p.m. on Sunday, "drawing a large crowd of spectators and triggering chaos," a police spokesman was quoted by Xinhua as saying.
Order was restored after about four hours and several people were arrested, said the company, a unit of Taiwan's Hon Hai Precision Industry Co. It said 40 people were taken to hospitals for treatment.
The violence did not appear to be work-related, the company and police said. Comments posted on Chinese Internet bulletin boards said it might have erupted after a security guard hit an employee.
Photos posted on microblog service Sina Weibo showed broken windows, a burned vehicle and police with riot helmets, shields and clubs.
Phone calls to police headquarters and the Taiyuan city hall were not answered. People reached by phone at restaurants and other businesses in the area said they had no details about the clash.
In the past year, Foxconn has faced scrutiny over workers' complaints about wages and working hours. The company raised minimum pay and promised in March to limit hours after an auditor hired by Apple found Foxconn employees were regularly required to work more than 60 hours a week.
AP technology writer Peter Svensson in New York and AP researcher Flora Ji in Beijing contributed.
Foxconn Technology Group: www.foxconn.com