BEIJING—A labor watch group says thousands of workers at a Chinese factory that makes Apple's iPhones have gone on strike over increased quality control demands and having to work during an extended national holiday.

New York-based China Labor Watch says several iPhone 5 production lines at Foxconn's Zhengzhou factory are paralyzed after 3,000-4,000 workers went on strike after finding the new demands difficult to meet. They're also angry they were being forced to work during the Golden Week holiday.

Taiwan-based Foxconn Technology Group manufactures iPhones in China. The iPhone 5 debuted in September.

China Labor Watch says workers beat quality control inspectors, who also carried out a work stoppage after management ignored their complaints.

Last month, a brawl involving 2,000 workers broke out at Foxconn's factory in China's Taiyuan city.