Shanghai will require microblog users to register under their real names from Monday, state media said, the latest local government in China to implement the rule after a spate of violent protests.
Beijing and the southern province of Guangdong have also ordered users of weibos -- microblogs similar to Twitter -- to register using their real names, as authorities tighten their grip on the Internet.
The move comes amid a surge in social unrest that has been concentrated in the wealthy manufacturing heartland of Guangdong.
Residents protesting against land seizures and a power plant in the province recently posted photos and reports of their demonstrations on weibos, defying official efforts to block news of the incidents.
With more than half a billion Chinese now online, authorities are concerned about the power of the Internet to influence public opinion in a country that maintains tight controls on its traditional media outlets.
Shanghai said the new rules aim to "foster a healthy Internet culture" and improve management over social networking, the official Xinhua news agency reported late Sunday.
The guidelines will apply to both private and corporate users in Shanghai.
Previously, users have been able to set up weibo accounts under assumed names, making it more difficult for authorities to track them, and allowing them to set up new accounts if existing ones are shut down by censors.
Despite official censorship of the web, ordinary Chinese are increasingly using weibos to vent their anger and frustration over official corruption, scandals and disasters.
A weibo user is believed to have broken the news of a deadly high-speed rail crash in China in July that provoked widespread condemnation of the government -- much of it online.
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