The Chinese government has tightened its rules on internet usage to enforce a previous requirement that users fully identify themselves to service providers.
The move is part of a package of measures which state-run Xinhua news agency said would protect personal information. The BBC reports critics believe the government is trying to limit freedom of speech.
The measures formally require anyone signing agreements to access the internet, fixed-line telephones and mobile devices to provide network service operators with identification information known as real-name registration.
Real-name registration was supposed to be have been implemented in 2011 but was not widely enforced.
Network service providers will be required to stop the transmission of illegal information once it is spotted by deleting the posts and saving the records "before reporting to supervisory authorities".
Chinese authorities closely monitor internet content that crosses its borders and regularly block sensitive stories through use of what is known as the Great Firewall of China, the BBC reports.
However, it has not stopped hundreds of millions of Chinese using the internet, many of them using micro-blogging sites to expose, debate and campaign on issues of national interest.
In recent months, the internet and social media have been used to orchestrate mass protests and a number of corrupt Communist Party officials have been exposed by individuals posting criticisms on the internet.