Uncertainty was still stalking the city, as protesters were frustrated with a string of incidents in which people have been stabbed with hypodermic syringes since early August.

The rally came just a day after tens of thousands of people protested throughout the city against the syringe attacks.

Security forces on Friday used tear gas to disperse the crowd when they tried to break through police lines, the Xinhua News Agency said. It also confirmed more than 1,000 protesters “faced” armed police who blocked them from entering Nanhu Square, where the city government is located, at about 1:40 pm. 

Military wagons patrolled the area on Friday while security forces asked the public to show restraint.

“The armed police units are fulfilling our responsibilities in accordance with law. Please support our initiative and stop gathering,” police said through loudspeakers as paramilitary forces tried to restore order.

A number of other small-scale confrontations were reported in the city Friday, Xinhua said .

Public Security Minister Meng Jianzhu arrived in Urumqi on Friday to direct local work of defusing the ongoing unrest.

Restoring social order is the top priority for all Party and government officials in Xinjiang, Meng said, while warning “those involved in violence, assaults, vandalism, looting and burning, and those who disrupt social order by different means or undermine ethnic unity, shall be punished according to the law without exception, whatever their ethnicity is”.

He called the recent syringe attacks, which he said were premeditated, masterminded and conducted by law-breakers and instigated by ethnic separatist forces, was a continuation of the July 5 violence in the city.

The tense mood has taken its toll on people around the city.

“I bought a lot of food today. Who knows what will happen next,” said Luo Huanzhang, who just returned from a regular morning outdoor market on the Guangming Road.

The market was crowded and many people intended to stock up groceries, Luo said. Residents also keep their forays into public places short.

Police on Friday said hospitals in Urumqi are treating 531 victims of hypodermic needle attacks.

Statistics from the city’s 24 hospitals say 106 of the 531 were showing obvious signs of needle attacks, Xinhua said. The victims included ethnic Hans, Uygurs as well as Kazaks, it said.

Munire, a Uygur staff with the Islam Hotel in downtown Urumqi, said she too was afraid of the syringe attacks because she “looks like a Han person”.

“I just hope things can go back to the way it was before the July 5 riot. That’s the only way I can forget all that’s happened since then,” she told China Daily.

As of Wednesday, there were no deaths or symptoms of infectious diseases, viruses or toxic chemicals having been administered.

A total of 21 people were detained and four arrested in connection with the attacks, according to Xinhua.

Local authorities acknowledged the stabbings on Wednesday afternoon, after several hundred people took to the streets, demanding government action.

The latest protest has brought shadows to the 18^th Urumqi Fair, which opened Tuesday and was scheduled to run until Saturday. No official figure is available on how many among the 500 overseas businessmen from 29 countries and regions had left amidst syringe attacks and the protests thereof.

The citywide traffic curfew imposed following Thursday’s protest was still effective at the time of going to press.

Xinhua on Friday quoted a municipal government spokesman as saying authorities in Urumqi have banned “unlicensed marches, demonstrations and mass protests” since the evening before.

The city government has banned all gatherings, marches or protests on roads or other public venues in the open-air without having first obtained permits from the public security department, Xinhua said.

Aside from demanding security guarantees, the protesters on Thursday also called on the government to severely punish the offenders of the new violence and the killings on July 5.

The July 5 riot left at least 197 people, mostly Han residents, brutally slain and more than 1,700 injured, according to official statistics.

Han residents first protested against the July 5 violence, the most brutal in decades, and called for government protection two days later throughout the city, triggering a traffic curfew.

Local authorities have issued arrest warrants to 196 suspects and prosecuted 51 of them for their involvement in the riot.

The police have further requested the procuratorate to approve the arrest of another 239 suspects thought to be involved in 140 crimes. Another 825 are held in criminal detention, the regional information office said.

Han Chinese run away as armed police chase them off during a demonstration at the center of Urumqi in China's Xinjiang Autonomous Region, Sept 4, 2009.