At least 20 leading blog service providers in China, including U.S.-based Internet giants Yahoo and MSN, have signed an agreement that will help the government censor and identify bloggers.

The agreement, which was unveiled by the Internet Society of China (which is under China's Ministry of Information Industry) this week, "encourages" blog service providers to list contact information and register users under their real names before letting them post blogs.

The companies are also asked to delete "illegal and bad information in a timely manner," and to "protect the interests of the State and Party."

Paris-based Reporters Without Borders condemned the new Chinese policy. The media rights group said that while the agreement stops short of ordering companies to register bloggers, it pressures them to do so.

Yahoo, Google and other Internet companies have previously been criticized for bowing to the Chinese government's demands to censor Web sites and content.

The companies argue that they must comply with Chinese laws to continue operating there.

Some information for this report was provided by AFP.