The ban mandates Internet users must provide proof of their real identify when posting messages on more than 100,000 Web sites registered in Xiamen, the Times of London reported Saturday.

City officials acted after thousands of residents rallied each other through cell phone text messages and Internet blogs to march on the site of a $14 million chemical plant. Construction since has been stopped pending an investigation into environmental concerns, the Times reported.

Xiamen will be the first city in China to officially ban anonymous Internet postings, said Tian Feng, vice-director of the Xiamen Bureau of Industry and Commerce.

Censorship is common in China, where tens of thousands of government workers monitor the actions of China's 140 million Internet users, the Times said.

Dozens of Web journalists and Internet commentators are serving prison terms throughout China for alleged subversion.