Medical experts have ruled out the possibility that radioactive substances, anthrax and toxic chemicals were used in recent needle attacks.

He also called on local residents not to believe and spread rumors and to express their demands through legal channels.

The social order had returned to normal after the July 5 riot, but the enemies at home and abroad were not reconciled to failure and so they conducted the needle attacks to spark public panic and anger, Wang said.

The mass protests have affected normal life and production in Urumqi and put to test the unity, stability and harmony that people of all ethnic groups have been seeking and longing for for years, the official said.

RETURNING TO NORMALCY

Hundreds of armed police were seen in the People's Square at the city center. Police were still blocking Xinmin Road, which links to a viaduct leading to the southern part of the city, an area densely populated by Uygurs.

A fleet of six flower-decorated wedding cars passed a downtown street as police eased traffic restrictions imposed in the wake ofpublic protests.

Ba Bayisilong, a Uygur student in Xinjiang Education Institute, came back to school on Sunday, after a two-month summer vacation.

"I'm back from my home in southern Xinjiang. All my classmates have returned," said the computer science major.

China Mobile, the nation's largest telecom carrier, opened a sales booth on the school campus. A large crowd of students, including both Han and Uygur students, patronized the stall to buy phone cards.

Vehicles were back on the streets and residents were out for shopping. Tianshan Shopping Mall and Carrefour Supermarket at downtown streets were thronged, while public security staff asked customers to open their bags for security checking.

Newly-inaugurated Communist Party chief of Urumqi Zhu Hailun said Saturday his top priority is to restore public security.

Zhu's predecessor Li Zhi was removed from post, along with Xinjiang's police chief Liu Yaohua, on Saturday.

HARSH PUNISHMENT

Syringe attackers will be given harsh punishment in accordance with the law, said a notice jointly released by the city's court, prosecutor's office and police department late Sunday.

Those who stabbed others with syringe needles containing poisonous or harmful substances or contaminated with drugs may be sentenced to three years and more in prison, or life imprisonment and even death penalty, if convicted, said the notice.

Such acts constitute the crime of deploying dangerous substances to harm others as described in China's penal code, which is punishable by death if the consequence is grave, the document said.

Those who spread fake information about stabbing cases, which disturbed the social order, will also be detained or jailed.

Citizens are allowed to seize and turn over the people stabbing or having stabbed others to police stations.

The punishment of those who surrender themselves or squeal on others may be lightened or exempted.