Thousands of Foxconn plant workers went on strike on Friday in China. This is the same plant where iPhone 5 handsets are manufactured, and it has often been in the news for over-working its employees. China Labor Watch reported that the strike has paralyzed production of the iPhone 5, making it much more difficult for Apple to meet demand for its new smartphone.

Only just weeks ago, Apple kicked off sales of the iPhone 5, and since then, the company has been struggling with supply chain constraints, among other factors.

3,000 to 4,000 workers walked off the job on Friday afternoon to begin their strike.

"In addition to demanding that workers work during the holiday, Foxconn raised overly strict demands on product quality without providing worker training for the corresponding skills," says the labor watch group China Labor Watch.

"Additionally, quality control inspectors fell into conflicts with workers and were beat up multiple times by workers. Factory management turned a deaf ear to complaints about these conflicts and took no corrective measures."

The group did not mention when work will resume, but if Apple is to meet demand, the company and Foxconn have no choice but to give the workers what they so desire.

Both Apple and Foxconn have come under fire recently for poor worker conditions at the iPhone plant, and the companies responded by raising wages, improving safety measure, and reducing overtime.