SHANGHAI -- Foxconn Technology, a major supplier to some of the world's electronics giants, including Apple, said it had closed one of its large Chinese plants Monday after the police were called in to break up a fight among factory employees.
A spokesman said some people had been hurt and detained by the police after the disturbance escalated into a riot involving more than 1,000 workers late Sunday.
The company said the incident was confined to an employee dormitory and "no production facilities or equipment have been affected." It said the cause of the disturbance was still under investigation.
One Foxconn employee reached by telephone Monday afternoon, however, said the incident began when workers started brawling with security guards.
Unconfirmed photographs and video circulated on social networking sites, purporting to be from the factory, showed smashed windows, riot police officers and large groups of workers milling around. The Foxconn plant, in the Chinese city of Taiyuan, employs about 79,000 workers.
The Chinese state-run news media said 5,000 police officers had been called in to quell the riot.
A Foxconn spokesman declined to specify whether the Taiyuan plant made products for the Apple iPhone 5, which went on sale last week, but he said it supplied goods to many consumer electronics brands.
An employee at the Taiyuan plant, however, said iPhone components were made there. Most Apple-related production, though, takes place in other parts of China, particularly in the provinces of Sichuan and Henan. Apple could not be reached for comment.
Foxconn said it employs about 1.1 million workers in China.
Labor unrest in Taiyuan, in northern China's Shanxi province, comes as strikes and other worker protests appear to be increasing in frequency in China this year compared to last year, said Geoffrey Crothall, spokesman for the China Labor Bulletin, a nonprofit advocacy group in Hong Kong seeking collective bargaining and other protections for workers in mainland China.
Many of the protests this year appear to be related to the country's economic slowdown, as employees demand the payment of overdue wages from financially struggling companies, or insist on compensation when money-losing factories in coastal provinces are closed and moved to lower-cost cities in the interior.
But the level of labor unrest in China this year has not yet matched 2010, when a surge in inflation sparked a wave of worker demands for higher pay, Mr. Crothall said.
Mr. Crothall said that while the cause of the latest dispute in Taiyuan remained unclear, his group had found an online video of police there using a megaphone to address "workers from Henan" – the adjacent province to the south of Shanxi. The police officer said that the workers' concerns would be addressed.
Disputes involving large groups of migrant workers are common in China. In some cases, workers protest after believing that they have been promised a certain pay package and traveled a long distance to claim it, only to find on arrival that the details are different from what they expected. In other cases, workers from different provinces with different cultural traditions coming together in a single factory have clashed over social issues or perceived slights.
The disturbance is the latest problem to hit Foxconn, which also is a key supplier to Dell, Hewlett-Packard and Microsoft.
Foxconn, which is part of Hon Hai Group of Taiwan, has been struggling to improve labor conditions at its China factories after reports about labor abuse and work safety violations.
Apple and Foxconn have worked together in the last year to improve conditions, raise pay and improve labor standards.
Mr. Crothall said workers in China had become increasingly emboldened.
"They're more willing to stand up for their rights, to stand up to injustice," he said, adding that damage to factory buildings and equipment still appeared to be unusual, occurring in fewer than 1 in 20 protests.
The same Taiyuan factory was the site of a brief strike during a pay dispute last March, the Hong Kong news media reported then.
Social media postings suggested that some injuries might have occurred when people were trampled in crowds of protesters.
This article originally appeared in The New York Times.