Violence erupted at Foxconn Zhengzhou, the world’s largest iPhone factory, with hundreds of workers smashing surveillance cameras and windows, viral videos on social media showed.

The latest industrial unrest at Foxconn's flagship factory in Zhengzhou city comes amid rising anger against country's draconian COVID rules as well as poor working conditions at the world's largest contract electronic manufacturer.

In one video clip, hundreds of workers were seen marching down a road, throwing sticks and bricks at anti-riot police standing in front of them. Another video showed a large group of workers on the side of a road being hemmed in by a wall of hazmat-suited personnel. Anger among the workers is also attributed to a sudden change in conditions for allowances given for retaining the workers inside the premise.

In another viral video, workers were seen smashing up Covid-19 testing kiosks with steel bars, chairs and fire extinguishers.

The immediate trigger for the protests, which began early on Wednesday (Nov 23), appeared to be a plan to delay bonus payments. Some workers complained of inadequate curbs in place to contain an outbreak including sharing dormitories with colleagues who had been confirmed as having Covid-19

In an official statement, Foxconn acknowledged that there had been public protests and “violence” at the factory.

“With respect to violence, the company will continue to communicate with employees and the government to prevent similar incidents from happening again”, the company said in a statement.

Foxconn is Apple's biggest iPhone maker, contributing 70% of iPhone shipments globally. It makes most of the phones at the Zhengzhou plant, though it has other production sites in India and southern China.