AP reports:

For much of the afternoon, a mob of 1,000 mostly young Han Chinese holding cleavers and clubs and chanting "Defend the country" tore through streets trying to get to a Uighur neighborhood until they were repulsed by police firing tear gas.
How did the local Chinese authorities respond to this? By urging them to go home, and trying to maintain an even hand while they sort out what happened? Not exactly ...
On Tuesday, some among the Han Chinese mob retreating from the tear gas were met by Urumqi's Communist Party leader Li Zhi, who climbed atop a police vehicle and started chanting with the crowd. Li pumped his fists, beat his chest, and urged the crowd to strike down Kadeer, the 62-year-old Uighur leader.
That'll help.