President Hu Jintao abruptly left the G8 summit in Italy to deal with deadly rioting in the northwest part of his country. On Sunday, rioting in Urumqi killed at least 156 people. It was set off by an earlier brawl at a factory in Guangdong, in the southeastern part of the country. The incidents dramatize the grievances of the Uighurs, one of 55 officially recognized minority groups which make up almost 10 percent of China's population. Frederick Starr is Chairman of the Central Asia-Caucasus Institute.