TIANJIN, Oct. 14 (Xinhua) -- China's anti-cyber virus authorities warned on Sunday that a new virus, transmitted by Microsoft's MSN (Microsoft Service Network) instant messaging program, can steal registered users' accounts and passwords, eventually causing economic losses.

On the computer hit by the virus, the MSN friend list will display a message telling the user's account has been cancelled and recommending a Website where the user can find out who did this, said experts with the Tianjin-based National Computer Virus Emergency Response Center.

When the user logs in the Website the message names, he is required to key in his account and password.

Those Websites, usually ended with "tk", "hk" and "cn," aim at procuring others' personal information, said the experts.

Once the illegal Websites obtain a user's account and password, they will log in MSN messenger in name of the user and send the similar fraudulent messages to those users on his friend list. In this way, more registered MSN users are prone to economic losses.

China has seen a booming instant messaging (IM) market with the success of MSN, Tecent's QQ, Yahoo Messengers and Skype. Statistics show that registered users of Skype in Chinese mainland have soared to over 25 million.

Internet security problems have also been on a rise in the past three years, which are mainly triggered by a growing number of profit-driven computer virus writers, hackers and illegal traders, according to a report by the Ministry of Public Security in September.

Viruses infected nearly one million Chinese computers over the weeklong National Day holiday from Oct. 1 to 7. The computers were infected by three different types of viruses and 118,000 computers crashed on one day alone.