Minister of Public Security Guo Shengkun, who arrived in Xinjiang on Wednesday afternoon to guide the investigation, said earlier that the ministry is working with the National People's Congress Standing Committee, the top legislature, on new legislation to deal with terrorism, organized crime and criminal activities masterminded through the Internet.

The potential laws, which China urgently needs in view of the current situation, will help safeguard national security and maintain social stability, he said.

Guo was delivering a report to the Standing Committee.

China does not have a specific law to deter terrorist activities, although the top legislature in 2011 approved a State Council document to allow the government to verify a list of terrorists and terrorist organizations, and freeze their assets.

In April 2012, the Ministry of Public Security released a list of six terrorists. Since then, the list has grown to at least 25 people. Their assets have been frozen.

Last week, nine people in Xinjiang stood trial at a court in Aksu prefecture for instigating ethnic hatred.

Ahetam Heli, one of the accused, was sentenced to six years' imprisonment after he was found to have used the Internet to promote religious extremism and to call for a "holy war" in November 2011.

Li Wei said police have been the primary target in terrorist attacks in Xinjiang.

He also said that Wednesday's rioting shows that attackers have turned to eastern Xinjiang, which has long been peaceful, after security was strengthened in southern Xinjiang, where several similar attacks occurred in recent years.

Xinhua and Zhao Yinan contributed to this story.