China will this week put more than 200 people on trial over last month's deadly ethnic unrest in Xinjiang, with security tight due to fears of fresh violence, state media said Monday.

The trials will take place in the Intermediate People's Court in Urumqi, the capital of the mainly Muslim northwest region where violence in early July left at least 197 people dead, the China Daily reported, citing unnamed officials.

The more than 200 defendants will face charges ranging from disrupting traffic to murder, the paper said, meaning that some of them could be given the death penalty. Authorities had previously announced only 83 formal arrests.

Armed police have started around-the-clock patrols in the area near the courthouse, in a massive security build-up ahead of the hearings, the paper said.

Local residents have voiced concerns that the trials will rekindle the same raw emotions among the city's different ethnic groups that fanned the deadly street clashes less than two months ago.

"Many bereaved Han families will come to wait for the verdicts, and the authorities fear they may clash with any Uighur in their presence," Guo Mei, a saleswoman who works near the court, told the China Daily.

The violence that broke out in Urumqi on July 5 pitted Han Chinese against Uighurs, a Turkic-speaking and predominantly Muslim people, in the worst ethnic unrest to hit the country in decades.

The paper reported intense public interest in the trials, which will all be public, except from those dealing with "splitting the state".

"I'd be very angry if those rioters receive light sentences or escape justice," said an unnamed worker. "They should be given harsh penalties for causing the loss of so many innocent lives."

One Han shopkeeper told the China Daily that Han Chinese who "overreacted" when seeking out Uighurs in retaliatory mob violence following the initial riots "should be granted leniency by the judge".

Both court officials and prosecutors declined to comment when contacted by AFP. A city government official surnamed Ma said he had "no information so far" about the trials.

With doubts remaining over who was to blame for the violence, the future of ethnic relations in volatile Xinjiang hinges to a large extent on how the Chinese government handles the aftermath, observers said.

"There is profound distrust on both sides in terms of Han Chinese and the Uighurs," Phelim Kine, an Asia researcher with New York-based Human Rights Watch, told AFP.

"The Chinese government can make a huge advance in terms of bridging that divide, in terms of bringing the two sides together, by allowing an independent investigation that all sides can point to as impartial and objective."

The paper did not say how many of the defendants were Uighurs. However, it reported that more than 170 Uighur and 20 Han lawyers had been assigned, suggesting that the bulk were members of the minority group.

Prosecutors have prepared more than 3,300 items of physical evidence for the trial, including bricks and clubs stained with blood, 91 video clips and more than 2,150 photos, the paper said.

Kine said HRW was concerned that the Urumqi trials "will follow the same abuses of international process that we saw in the trials of suspects detained following the unrest in Tibet in March 2008."