Beijing has ordered microbloggers to register their real names in a further tightening of control over China's hugely popular social media. They have three months to do so.
The BBC reports Twitter and Facebook are banned in China, but microblogs such as Sina Weibo have several hundred million users.
However, Xinhua news agency quoted the Beijing Internet Information Office as saying people will be able to choose their own user names.
Hong Kong media said the cities of Shanghai and Guangzhou were likely to follow suit.
Warnings have previously been issued that online content must be acceptable to the Communist Party.