A Han Chinese man holds a plank during demonstrations in Urumqi, Xinjiang Uighur Autonomous Region July 7, 2009. Riot police on Tuesday fired tear gas to try to break up rock-throwing Han and Uighur protesters who clashed in the capital of China's Muslim region of Xinjiang two days after bloody clashes killed 156 and wounded more than 1,000. REUTERS/ Nir Elias (CHINA POLITICS CRIME LAW CONFLICT)