Foxconn workers are blaming company security officers for Sunday’s unrest at a manufacturing facility in China, claiming that the mass riot was the result of an escalating brawl between assembly line workers and security guards, according to an article from the IDG News Service.

The riot involved 2,000 workers, and it occurred at a Foxconn factory in the Chinese city of Taiyuan and sent 40 people to the hospital before it was stopped by local police, the article says. While Foxconn states that the incident arose from a “personal dispute,” without elaborating, company workers interviewed Tuesday say the riot started as a fight between only a few security officers and workers.

Although the instigation behind the fight is unclear, workers say it’s well-known that Foxconn security officers are often domineering and aggressive toward assembly-line workers. The unrest also came as workers from Foxconn’s other manufacturing facilities in China have been transferred to the Taiyuan facility to learn how to assemble the iPhone 5, the IDG article says.

The new transfers are less tolerant of Foxconn’s security officers, explained a 20-year-old worker. “I think some of these transfers were more extreme in their approach. The workers native to Taiyuan also probably couldn’t take it any more with the guards,” he says.

When Sunday’s fight broke out, hundreds of workers from nearby dormitories came out to watch as the crowd erupted into a riot targeting the company’s security officers. This led to destruction of cars and store windows on the Foxconn campus, the article says.

The facility employs 79,000 people, and although it was closed Monday, it reopened Tuesday, with police cars and vans stationed on street corners in the area, IDG reports.

The Taiwanese company also counts Sony, Microsoft and Nintendo among its customers, and it has faced ongoing criticism for poor working conditions at its factories. Labor groups point to Sunday’s riot as a symptom of employee mistreatment, the article says.

Workers interviewed at the factory offer mixed views of their own jobs, some saying that the wages are too low – around $395 a month depending on overtime – and others saying that the jobs are easy to get and require little education.

The workers seemed unanimous in their negative opinions of the Foxconn security officers, alleging that the officers would sometimes bully or berate employees for not following proper procedures, such as smoking in non-smoking areas, forgetting an ID card to pass a security checkpoint, or bringing friends onto the employee-only campus, the article says.

Foxconn did not comment on these allegations, however, following the riot, some workers noted that security officers at the facility have been treating workers with more respect.