BEIJING: A Chinese court on Monday opened the first criminal trials over violent ethnic riots in the western Xinjiang region in July that left nearly 200 people dead, state media reported.

The court in the Xinjiang regional capital of Urumqi began hearing three cases involving seven defendants accused of participating in the rioting, China Central Television (CCTV) reported, giving no other details on the charges.

Urumqi erupted in chaos on July 5 as members of the ethnic Uighur minority -- most of whom are Muslims went on a rampage in attacks directed mainly at members of China's dominant Han ethnic group.

The riots were the worst ethnic violence in China in decades, leaving 197 people dead, most of them Han, according to the government.

Police have detained at least 718 people suspected of crimes related to the unrest, earlier reports said.

State-controlled Xinhua news agency quoted the city's prosecutor late last month saying 21 people had so far been charged with crimes including homicide, arson, robbery and property damage related to the riots.

Footage broadcast by CCTV showed deserted streets in front of the Urumqi court, with riot police out in force.

Urumqi has been under extremely heavy security since the riots, tightened anew amid a wave of needle attacks beginning in late August which Han have blamed on Uighurs.

The only defendant identified by CCTV in Monday's trials appeared to have a Uighur name. It said a verdict could come later in the day.

One man was sentenced to death and a second handed a life prison term on Saturday over an ethnic brawl at a southern China factory that state media has said killed two Uighurs just before the July riots.

The incident has been widely blamed for outraging Uighurs and sparking the Urumqi riots.

Nine others were given jail terms of five to eight years over the fight in Guangdong province in late June that pitted Han and against Uighurs, a statement on the Guangdong provincial high court's website said.

China's roughly eight million Uighurs have long complained of religious, political and cultural oppression by Chinese authorities.

In an online video, a leading Al-Qaeda figure called on Uighurs to launch a holy war against China and urged Muslims worldwide to support their co-religionists, a US monitoring group reported last week.