BEIJING (AFP) - China on Thursday sentenced six more people to death over bloody ethnic unrest in its far-western Xinjiang region in July, bringing the total to 12 as it delivered tough retribution over the violence. Three of the six were given the death penalty with a two-year reprieve, a sentence usually commuted to life in prison, over the worst ethnic violence China had seen in decades. A court in the regional capital Urumqi sentenced three others to life in jail and five people to lesser prison terms for their role in the unrest that rocked the city, according to a Xinjiang government statement faxed to AFP. The violence erupted on July 5, pitting mainly Muslim minority Uighurs against members of Chinas dominant Han group, leaving 197 dead and more than 1,600 injured, according to an official toll. Han vigilantes then went on a rampage against Uighurs two days later, but the exact number of casualties from that day has never been divulged. A total of 21 defendants have been tried and convicted since Monday of murder and other crimes such as intentional damage to property, arson, and robbery. Security had been ratcheted up in Urumqi ahead of the trials. Six Uighurs were given the death penalty on Monday and another sent to prison for life, in a move that Uighur exiles said would further stoke ethnic tensions in the vast region bordering Central Asia. On Thursday, one man with a Han Chinese name Han Junbo was among those sentenced to death for beating a Uighur man to death, the statement said. Another apparently Han man, Liu Bo, was given a 10-year jail term. Six of the other defendants had names that appeared to be Uighur, and the rest were not immediately identified, according to the government statement. One of those sentenced to death, apparently a Uighur, was found guilty of beating two people to death with another defendant, as well as stealing peoples possessions, including mobile phones and bracelets. Uighur exiles strongly condemned the latest sentences, saying Uighur defendants were not given the right to choose their own lawyers, and were not allowed to meet with their families. Chinas sentences are intensifying the deterioration of the situation, and there are no Uighurs that can accept this type of abuse of justice, the World Uighur Congress said in a statement emailed to AFP. Rebiya Kadeer, the exiled leader of the congress who lives in the United States, said Tuesday during a visit to New Zealand that the death sentences would serve only to further enrage her people. Aside from the 21 tried this week, police have also detained around 700 people suspected of crimes related to the unrest, earlier reports have said. Residents in Urumqi contacted by AFP said Thursday the city was calm amid a heavy security presence. We dont worry too much but still we cannot relax our vigilance. The armed police are still on duty in bustling streets, a woman at a drug store, who refused to be named, said over the phone. China had vowed to come down hard on those found guilty, with President Hu Jintao and other top leaders saying the organisers, key members, and the serious violent criminals must be severely punished, Xinhua news agency said. The countrys roughly eight million Turkic-speaking Uighurs have long complained of religious, political and cultural oppression by Chinese authorities, and tensions have simmered in the Xinjiang region for years. China says it faces a serious terrorist threat from Muslim separatists in Xinjiang, but rights groups have accused Beijing of exaggerating the threat in order to justify very tight controls in the region. Authorities have blamed the Xinjiang unrest on ethnic separatists, without providing any evidence. But Uighurs say the violence was triggered when police cracked down on peaceful protests over a brawl in late June at a factory in southern China that state media said left two Uighurs dead. One ethnic Han man was sentenced to death and a second handed a life prison term over that brawl in verdicts announced on Saturday in southern China.