China enlists online firms to cleanse web of terror content

China has commenced a campaign to purge the internet of content it said promotes terror and violence, enlisting the aid of major websites as the country moves to stamp out violence in its restive far west.

China has blamed a series of attacks in the Xinjiang region on Islamist separatists the government says seek to establish an independent state called East Turkestan.

A suicide bombing last month killed 39 people at a market in Xinjiang's capital of Urumqi. In March, 29 people were stabbed to death at a train station in the southwestern city of Kunming.

"Terror video and audio products have become a major instigator of the high incidence of terrorist activities at present," the official Xinhua news agency said, quoting a statement from the State Internet Information Office.

The government aims to stop circulation in China of terror-related materials made overseas, remove such information from the internet, punish websites that break the rules and urge internet firms to "uphold their responsibilities", Xinhua said.

China already exercises tight control over the internet, with the cooperation of the country's internet companies.

Beijing said most suspects in recent cases had been spurred by terror video and audio products to carry out attacks.

"Many of them had learned how to make explosives through online tutorials," Xinhua said. "They exchanged experiences of making explosives and propagating jihad through chat tools, text messages and illegal preaching sites."

China faces a serious challenge cleaning the web of such content, as the volume of materials released by the East Turkestan Islamic Movement -- the main terror group in China's eyes -- has increased dramatically, the report added.

"These materials, which propagate jihad, terrorism and religious extremism, have been spread incessantly in China," the statement said. "They have had a strong instigation effect and are extremely harmful."

It is unclear how broadly the government will define terror-related content.

Websites aimed at ethnic Uighurs, Tibetans and Mongols have been banned in the past following government accusations that they spread separatism, although rights groups say they simply provide a forum for discussion about issues like discrimination.

More than 30 internet companies, including Sina, top search engine Baidu , Tencent Holdings and Alibaba Group's eBay-like Taobao had signed "a letter of commitment" to clear out terror-related material.

"Fighting against online terror audio and video materials is our most important political task now," Xinhua quoted Zhao Tian, deputy editor-in-chief of Sina.com, as saying.

Those providing tip-offs to terror-related information online will get rewards of up to 100,000 yuan (A$17,100), the report added.

Exiled Uighur groups and human rights activists say the government's own repressive policies in Xinjiang have provoked unrest, something Beijing denies, and have expressed doubt there exists a coherent extremist movement as China claims.