BEIJING - To prevent the use of fake identities and make it easier to trace the source of online rumors, Sina Weibo, which runs the most popular micro blog website in China, has set up a system to verify the identities of users.

Micro-bloggers can now go to the site and voluntarily submit their names, ID numbers and their cell phone numbers. Sina Weibo will then have public security departments check that information for accuracy, Mao Taotao, a public relations manager at Sina, said on Friday.

He said micro-bloggers whose ID numbers jibe with police records will receive an "honor medal", which will be displayed under their user names on the website.

"We are encouraging micro-bloggers to apply for the real-name system, but we don't expect all users to do that," he said.

Before the service was started, Sina Weibo had begun adding a capital letter V behind the user names of celebrities, influential people and various big organizations on the site.

So far, more than 300,000 micro-bloggers have a "V" after their user names, the company said.

"The new policy, together with the previous one, will help to keep things clean online," Mao said.

He said the company's "rumor-control" team will work around the clock to monitor Weibo posts and remove false information.

Tan Chao, director of the team, said the identity system will make it easier to find Weibo users who have fake identities and to eradicate online rumors. He said posts containing false information must be eliminated as soon as possible.

Tan noted the recent deletion of a post containing false information. It said several people had taken syringes containing HIV to Beijing to use in attacks against others.

Two micro-bloggers were found to be responsible for the information, the Beijing public security bureau said on Thursday.

One of the men, surnamed Li, was given criminal detention for writing the post, and the other, surnamed Liu, was admonished for forwarding it without confirming its accuracy, according to the police.

"The police will crack down on online rumors and we are asking residents and netizens to report fake information to us," said Zi Xiangdong, spokesman of the Beijing public security bureau.

However, the new policy raises concern among Weibo users.

"I will not submit my personal information to the company, because I'm afraid my information might be leaked when the company transfers it to the police for validation," said Zhang Fan, an employee at a media company in Beijing.

"Besides, the honor medal does not appeal to me at all," she added.

Liu Honghui, a Beijing lawyer specializing in online cases, said the identity system will be helpful in cases in which someone has pirated other people's identities to spread rumors.

Meanwhile, he emphasized that the company and government departments should manage private information properly.