BEIJING (AP) — The company that makes Apple’s iPhones suspended production at a factory in China on Monday after a brawl by as many as 2,000 employees at a dormitory injured 40 people.

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.

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.

Photos posted on microblog service Sina Weibo showed broken windows, a burned vehicle and police with riot helmets, shields and clubs.

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.

• Associated Press