The company that makes Apple's iPhones suspended production at a factory in China on Monday after a fight involving as many as 2,000 employees.

The clash, the cause of which was under investigation, erupted Sunday night at a privately managed dormitory near Foxconn Technology Group's 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.

Violence was brought under control after about four hours and 40 people were taken to hospitals for treatment, the Taiwanese-owned company said. It said several people were detained by police.

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.

People reached by phone at restaurants and other businesses in the area said they had no details about the clash.

Foxconn, owned by Taiwan's Hon Hai Precision Industry Co., said production at the factory was suspended and would resume Tuesday. It declined to say whether the factory, which employs 79,000 people, was involved in iPhone production.

Photos posted on microblog service Sina Weibo showed broken windows and a burned vehicle. Other photos showed police with riot helmets, shields and clubs walking down the street and numerous police vehicles parked nearby.

The fight started at 11 p.m. on Sunday at the dormitory, "drawing a large crowd of spectators and triggering chaos," a police spokesman was quoted by Xinhua as saying.

Foxconn is one of China's biggest employers, with some 1.2 million workers in factories across the country.

The company has faced scrutiny over complaints in the past about wages and working hours. It raised minimum pay and promised in March to limit hours after an auditor hired by Apple Inc. found Foxconn employees regularly were required to work more than 60 hours a week.

Foxconn makes iPhones and iPads for Apple and also assembles products for Microsoft Corp. and Hewlett-Packard Co. In addition to Taiyuan, it has factories in the southern city of Shenzhen, in Chengdu in the west and in Zhengzhou in central China.