Videos -- which the BBC was not able to verify -- show hundreds of workers marching, with some confronted by people in hazmat suits and riot police.

Last month, a surge in Covid cases saw the company lock down the campus, prompting some workers to break out.

Later, the factory operated by Foxconn, a global electronics contract manufacturer, recruited new workers with the promise of generous bonuses, BBC reported.

Footage shared on a live streaming site showed workers shouting, "Defend our rights! Defend our rights!"

Other workers were seen smashing surveillance cameras and windows with sticks.

Several clips also showed workers complaining about food they had been given and saying they had not received bonuses as promised.

One Foxconn employee who recently started working at the Zhengzhou plant told the BBC workers were protesting because Foxconn had "changed the contract they promised".

He also said some newly recruited workers feared getting Covid from the staff who had been there during the earlier outbreak.

"Those workers who are protesting are wanting to get a subsidy and return home," the staff member said.

"There was a heavy police deployment to the plant on Wednesday morning, he said.

Foxconn has not yet commented.

It is Apple's main subcontractor and its Zhengzhou plant assembles more iPhones than anywhere else in the world.

In late Oct., many workers fled the plant amid rising Covid cases and allegations of poor treatment of staff, their escape captured on social media as they rode lorries back to their hometowns elsewhere in the central Chinese province, the BBC reported.

Foxconn then attempted to convince workers to stay and to recruit new staff by offering higher salaries and bonuses.
The firm has since enacted so-called closed loop operations at the plant -- keeping it isolated from the wider city of Zhengzhou because of a Covid outbreak there.

Earlier this month Apple said it expected lower shipments of iPhone 14 models because of the disruption to production in Zhengzhou.