Authorities aim to root out audio and video products involving terrorism and violence on the Internet within six months to safeguard social stability, especially in the Xinjiang Uygur autonomous region.

The State Internet Information Office launched the online cleanup campaign on Friday, asking Web companies to supervise and eliminate terrorism-related content.

More than 30 enterprises, including Internet giant Sina and video platform Youku, also signed an agreement on improving management of online information. They promised not to provide access to, and the means to spread, terrorism-related information.

Companies are required to build a special platform for residents' reports, disclose hotline numbers and reward those supplying important clues. The maximum reward is 100,000 yuan ($16,000), the office said.

A spokesman for the office said video and audio products have become a major source of the high number of terrorist activities. He added that most terrorists had listened to or watched terrorism-related information online before taking part in attacks.

Some audio and video reports distorted religions and incited terrorist attacks, while others provided information on how to make explosives and intensify ethnic conflicts, he said.

Sina has formed a group to handle terrorism-related work since March 1, when attackers killed 29 civilians and injured another 143 at a railway station in Kunming, Yunnan province.

Company spokesman Zhao Tian said that so far two items of information involving religious extremism have been deleted, while another 800 messages relating to guns and violence have been wiped.

Some enterprises, including technology giant Tencent and e-commerce firm Alibaba, have added employees to supervise efforts and invited Uygur-language speakers to check content.

Li Wei, an anti-terrorism expert, suggested the government publish a specific definition of terrorist information quickly and provide more knowledge, such as detecting signs of religious extremism, for companies through training.

caoyin@chinadaily.com.cn