URUMQI: Authorities in  Urumqi city said Tuesday 83 suspects had been arrested for being implicated in the July 5 riot which left 197 people dead and more than 1,600 injured.

Procurator Utiku'er Abudrehman made the announcement at a press conference Tuesday in Urumqi, capital of Xinjiang Uygur Autonomous Region.    

It is the first time Urumqi authorities have officially announced formal arrests.    

He said those arrested will face charges including murder, intentional injury, arson and robbery.    

At the same briefing Urumqi city police chief Chen Zhuangwei said a total of 718 had now been detained on suspicion of being implicated in the riot.

Chen, head　of　the　Public　Security Department　of　Urumqi, said collecting evidence had been a tough task for the city's police force. It had involved examinations at　the　crime scenes and DNA evaluations, but it had been carried out swiftly.    

Chen said police had visited more than 1,000 people, including those injured in the riot and families whose members had lost their lives in the unrest.

Police had also inspected 530 shops and 943 motor vehicles damaged during the violence. They collected and examined 3,318 pieces of evidence, and obtained 2,169 photos and 91 groups of video clippings of crime scenes in Urumqi.