Uighur men wait for the beginning of Friday prayers outside the Altyn Mosque in Yarkand, in the region of Xinjiang April 4, 2008. China is on guard against unrest in the region, home to its ethnic Uighur minority, a Muslim Central Asian people, following a demonstration in the Xinjiang town of Hetian and after widespread protests in Tibet. REUTERS/Nir Elias (CHINA)